Neutralizing determinants of IL-17 Receptor A and antibodies that bind thereto

ABSTRACT

The present invention relates to the identification of neutralizing determinants on IL-17 Receptor A (IL-17RA or IL-17R) and the antigen binding proteins, such as antibodies, that bind thereto and inhibit IL-17 ligand family members from binding to and activating IL-17 Receptor A or a receptor complex comprising IL-17 Receptor A.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119 of U.S. Provisional Application Ser. No. 60/969,895, filed Sep. 4, 2007, U.S. Provisional Application Ser. No. 60/873,072, filed Dec. 5, 2006 and U.S. Provisional Application Ser. No. 60/827,882, filed Oct. 2, 2006, which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to the identification of neutralizing determinants on IL-17 Receptor A (IL-17RA or IL-17R) and antibodies that bind thereto. Aspects of the invention also include antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein.

BACKGROUND

IL-17A and IL-17F bind and activate IL-17RA. IL-17RA has been shown to be important in regulating immune responses. Activation of the IL-17RA leads to production of cytokines, chemokines, growth factors, and other proteins that contribute to the symptoms and/or pathology of numerous diseases. IL-17A is an inflammatory cytokine that induces the production of cytokines and other mediators leading to diseases and physiological effects such as inflammation, cartilage degradation, and bone resorption. IL-17A also plays a role in a number of inflammatory conditions including arthritis (rheumatoid arthritis), psoriasis, inflammatory bowel disease, multiple sclerosis, and asthma. (Li et al., 2004, Huazhong Univ. Sci. Technolog. Med. Sci. 24:294-296; Fujino et al., 2003, Gut. 52:65-70; Kauffman et al., 2004, J. Invest. Dermatol. 123:1037-1044; Mannon et al., 2004, N. Engl. J Med. 351:2069-2079; Matusevicius et al., 1999, Mult Scler 5, 101-104; Linden et al., Eur Respir J. 2000 May; 15(5):973-7; Molet et al., 2001, J. Allergy Clin. Immunol. 108:430-438). Recent studies have suggested that IL-17F plays a role in the induction of inflammatory responses (Oda et al., 2006, American J. Resp. Crit. Care Medicine, Jan. 15, 2006; Numasaki et al., 2004, Immunol Lett. 95:97-104).

Aspects of the invention provide for the identification of neutralizing determinants on IL-17RA that neutralizing antibodies bind and thereby inhibit IL-17 ligand family members from binding to and activating IL-17 Receptor A or a receptor complex comprising IL-17 Receptor A. Aspects of the invention also include antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a phylogenetic dentogram analysis of the CDRs (complementarity determining regions) of the variable heavy (V_(H)) and variable light (V_(L)) domains of various IL-17R antigen binding proteins (antibodies).

FIG. 2 depicts an alignment of the amino acid sequences of the CDRs of the variable heavy (V_(H)) domains of various IL-17R antigen binding proteins (antibodies). The CDR1, CDR2, and CDR3 regions are highlighted.

FIG. 3 depicts an alignment of the amino acid sequences of the CDRs of the variable light (V_(L)) domains of various IL-17R antigen binding proteins (antibodies). The CDR1, CDR2, and CDR3 regions are highlighted.

FIG. 4 shows dose-dependent inhibition by an IL-17RA mAb in a wild-type (WT) collagen-induced arthritis (CIA) model. A P<0.05 was seen when comparing IL-17RA mAb at 100 μg and 300 μg treatment groups versus control treatment group (days 13, 15 and 16).

FIG. 5 shows the results of therapeutic treatment with IL-17RA mAb. The data shows stabilized mean clinical scores in wild-type mice in a standard CIA model of arthritis. These data demonstrate that IL-17RA inhibition by an IL-17RA antigen binding protein may be therapeutically useful in treating rheumatoid arthritis (RA), especially in the preservation of joint bone and cartilage.

FIG. 6 shows that therapeutic treatment with IL-17RA mAb stabilized mean clinical scores in TNFR p55/p75 knockout mice in a standard CIA model of arthritis. These data show that IL-17RA inhibition by an IL-17RA antigen binding protein may be therapeutically useful in treating RA, especially in the preservation of joint bone and cartilage. Notably, IL-17RA inhibition was able to stabilize disease in a model independent of TNF signaling.

FIG. 7 shows exemplary IL-17RA human mAbs (AM_(H)14/AM_(L)14, AM_(H)22/AM_(L)22, AM_(H)19/AM_(L)19, and AM_(H)18/AM_(L)18) were able to inhibit cynomologous IL-17-induced IL-6 production from JTC-12 cells (cynomologous kidney cell line). The (----) line depicts the positive control value of cynomologous IL-17 in combination with TNF-alpha. The (-.-.-) line depicts the positive control value of cynomologous TNF-alpha. The (....) line depicts the media control value.

FIGS. 8A and 8B show the results of multiplexed binning of IL-17RA antibodies. Shaded values indicate antibody pairs that can bind to IL-17RA simultaneously, suggesting that these antibodies bind to different neutralizing determinants. Boxed values indicate antibodies paired against themselves.

FIG. 9 shows mouse IL-17RA (SEQ ID NO:432) and the 5 domains, A, B, C, D, E, and F that replaced the counterpart domains in the human IL-17RA sequence.

FIGS. 10A-10D shows the amino acid sequences for human and mouse IL-17RA and human/mouse chimeric IL-17RA proteins.

FIG. 11 is a table summarizing the IL-17RA mAbs capacity to bind the various chimeric proteins. Shaded values denote where the IL-17RA mAbs lost binding to that particular chimera (n.d. means not determined).

FIG. 12 depicts the amino acid residues that were replaced with an arginine residue in SEQ ID NO:431.

FIG. 13 illustrates titration curves of various IL-17RA mAbs binding to the D152R IL-17RA mutant.

FIG. 14 is a summary of the arginine scan, binning, and chimera data for various IL-17RA mAbs.

DETAILED DESCRIPTION OF THE INVENTION

The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

Standard techniques may be used for recombinant DNA, oligonucleotide synthesis, tissue culture and transformation, protein purification etc. Enzymatic reactions and purification techniques may be performed according to the manufacturer's specifications or as commonly accomplished in the art or as described herein. The following procedures and techniques may be generally performed according to conventional methods well known in the art and as described in various general and more specific references that are cited and discussed throughout the specification. See, e.g., Sambrook et al., 2001, Molecular Cloning. A Laboratory Manual, 3^(rd) ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., which is incorporated herein by reference for any purpose. Unless specific definitions are provided, the nomenclature used in connection with, and the laboratory procedures and techniques of, analytical chemistry, organic chemistry, and medicinal and pharmaceutical chemistry described herein are those well known and commonly used in the art. Standard techniques may be used for chemical synthesis, chemical analyses, pharmaceutical preparation, formulation, and delivery and treatment of patients.

Aspects of the invention include, but are not limited to: Embodiment one: An isolated monoclonal antibody, or IL-17RA-binding fragment thereof, that specifically binds to IL-17RA and competes for binding with an antibody selected from the group consisting of:

-   -   A. an isolated antibody, or IL-17RA-binding fragment thereof,         comprising         -   a. a light chain variable domain sequence that is at least             80% identical to a light chain variable domain sequence of             AM_(L)2, 3, 5, 9, 10, 12, 14-17, and 19-25 (SEQ ID NOs:28,             29, 31, 35, 36, 38, 40-43, and 45-53, respectively);         -   b. a heavy chain variable domain sequence that is at least             80% identical to a heavy chain variable domain sequence of             AM_(H)2, 3, 5, 9, 10, 12, 14-17, and 19-25 (SEQ ID NOs:2, 3,             5, 9, 10, 12, 14-17, and 19-25, respectively);         -   c. the light chain variable domain of (a) and the heavy             chain variable domain of (b); wherein said antibody             specifically binds to human IL-17RA;     -   B. an isolated antibody, or IL-17RA-binding fragment thereof,         comprising         -   a. a light chain CDR1 (SEQ ID NO:188), CDR2 (SEQ ID NO:189),             CDR3 (SEQ ID NO:190) and a heavy chain CDR1 (SEQ ID NO:110),             CDR2 (SEQ ID NO:111), CDR3 (SEQ ID NO:112) of antibody AM-2;         -   b. a light chain CDR1 (SEQ ID NO:191), CDR2 (SEQ ID NO:192),             CDR3 (SEQ ID NO:193) and a heavy chain CDR1 (SEQ ID NO:113),             CDR2 (SEQ ID NO:114), CDR3 (SEQ ID NO:115) of antibody AM-3;         -   c. a light chain CDR1 (SEQ ID NO:197), CDR2 (SEQ ID NO:198),             CDR3 (SEQ ID NO:199) and a heavy chain CDR1 (SEQ ID NO:119),             CDR2 (SEQ ID NO:120), CDR3 (SEQ ID NO:121) of antibody AM-5;         -   d. a light chain CDR1 (SEQ ID NO:209), CDR2 (SEQ ID NO:210),             CDR3 (SEQ ID NO:211) and a heavy chain CDR1 (SEQ ID NO:131),             CDR2 (SEQ ID NO:132), CDR3 (SEQ ID NO:133) of antibody AM-9;         -   e. a light chain CDR1 (SEQ ID NO:212), CDR2 (SEQ ID NO:213),             CDR3 (SEQ ID NO:214) and a heavy chain CDR1 (SEQ ID NO:134),             CDR2 (SEQ ID NO:135), CDR3 (SEQ ID NO:136) of antibody             AM-10;         -   f. a light chain CDR1 (SEQ ID NO:218), CDR2 (SEQ ID NO:219),             CDR3 (SEQ ID NO:220) and a heavy chain CDR1 (SEQ ID NO:140),             CDR2 (SEQ ID NO:141), CDR3 (SEQ ID NO:142) of antibody             AM-12;         -   g. a light chain CDR1 (SEQ ID NO:224), CDR2 (SEQ ID NO:225),             CDR3 (SEQ ID NO:226) and a heavy chain CDR1 (SEQ ID NO:146),             CDR2 (SEQ ID NO:147), CDR3 (SEQ ID NO:148) of antibody             AM-14;         -   h. a light chain CDR1 (SEQ ID NO:227), CDR2 (SEQ ID NO:228),             CDR3 (SEQ ID NO:229) and a heavy chain CDR1 (SEQ ID NO:149),             CDR2 (SEQ ID NO:150), CDR3 (SEQ ID NO:151) of antibody             AM-15;         -   i. a light chain CDR1 (SEQ ID NO:230), CDR2 (SEQ ID NO:231),             CDR3 (SEQ ID NO:232) and a heavy chain CDR1 (SEQ ID NO:152),             CDR2 (SEQ ID NO:153), CDR3 (SEQ ID NO:154) of antibody             AM-16;         -   j. a light chain CDR1 (SEQ ID NO:233), CDR2 (SEQ ID NO:234),             CDR3 (SEQ ID NO:235) and a heavy chain CDR1 (SEQ ID NO:155),             CDR2 (SEQ ID NO:156), CDR3 (SEQ ID NO:157) of antibody             AM-17;         -   k. a light chain CDR1 (SEQ ID NO:239), CDR2 (SEQ ID NO:240),             CDR3 (SEQ ID NO:241) and a heavy chain CDR1 (SEQ ID NO:161),             CDR2 (SEQ ID NO:162), CDR3 (SEQ ID NO:163) of antibody             AM-19;         -   l. a light chain CDR1 (SEQ ID NO:242), CDR2 (SEQ ID NO:243),             CDR3 (SEQ ID NO:244) and a heavy chain CDR1 (SEQ ID NO:164),             CDR2 (SEQ ID NO:165), CDR3 (SEQ ID NO:166) of antibody             AM-20;         -   m. a light chain CDR1 (SEQ ID NO:245), CDR2 (SEQ ID NO:246),             CDR3 (SEQ ID NO:247) and a heavy chain CDR1 (SEQ ID NO:167),             CDR2 (SEQ ID NO:168), CDR3 (SEQ ID NO: 169) of antibody             AM-21;         -   n. a light chain CDR1 (SEQ ID NO:248), CDR2 (SEQ ID NO:249),             CDR3 (SEQ ID NO:250) and a heavy chain CDR1 (SEQ ID NO:170),             CDR2 (SEQ ID NO:171), CDR3 (SEQ ID NO:172) of antibody             AM-22;         -   o. a light chain CDR1 (SEQ ID NO:251), CDR2 (SEQ ID NO:252),             CDR3 (SEQ ID NO:253) and a heavy chain CDR1 (SEQ ID NO:173),             CDR2 (SEQ ID NO:174), CDR3 (SEQ ID NO:175) of antibody             AM-23;         -   p. a light chain CDR1 (SEQ ID NO:254), CDR2 (SEQ ID NO:255),             CDR3 (SEQ ID NO:256) and a heavy chain CDR1 (SEQ ID NO:173),             CDR2 (SEQ ID NO:174), CDR3 (SEQ ID NO:175) of antibody             AM-23;         -   q. a light chain CDR1 (SEQ ID NO:257), CDR2 (SEQ ID NO:258),             CDR3 (SEQ ID NO:259) and a heavy chain CDR1 (SEQ ID NO:176),             CDR2 (SEQ ID NO:177), CDR3 (SEQ ID NO:178) of antibody             AM-24;         -   r. a light chain CDR1 (SEQ ID NO:260), CDR2 (SEQ ID NO:261),             CDR3 (SEQ ID NO:262) and a heavy chain CDR1 (SEQ ID NO:179),             CDR2 (SEQ ID NO:180), CDR3 (SEQ ID NO:181) of antibody             AM-25;         -   wherein said antibody specifically binds to human IL-17RA;             and     -   C. an isolated antibody, or IL-17RA-binding fragment thereof,         comprising         -   a. a light chain variable domain and a heavy chain variable             domain of AM_(L)2/AM_(H)2 (SEQ ID NO:28/SEQ ID NO:2);         -   b. a light chain variable domain and a heavy chain variable             domain of AM_(L)3/AM_(H)3 (SEQ ID NO:29/SEQ ID NO:3);         -   c. a light chain variable domain and a heavy chain variable             domain of AM_(L)5/AM_(H)5 (SEQ ID NO:31/SEQ ID NO:5);         -   d. a light chain variable domain and a heavy chain variable             domain of AM_(L)9/AM_(H)9 (SEQ ID NO:35/SEQ ID NO:9);         -   e. a light chain variable domain and a heavy chain variable             domain of AM_(L)10/AM_(H)10 (SEQ ID NO:36/SEQ ID NO:10);         -   f. a light chain variable domain and a heavy chain variable             domain of AM_(L)12/AM_(H)12 (SEQ ID NO:38/SEQ ID NO:12);         -   g. a light chain variable domain and a heavy chain variable             domain of AM_(L)14/AM_(H)14 (SEQ ID NO:40/SEQ ID NO:14);         -   h. a light chain variable domain and a heavy chain variable             domain of AM_(L)15/AM_(H)15 (SEQ ID NO:41/SEQ ID NO:15);         -   i. a light chain variable domain and a heavy chain variable             domain of AM_(L)16/AM_(H)16 (SEQ ID NO:42/SEQ ID NO:16);         -   j. a light chain variable domain and a heavy chain variable             domain of AM_(L)17/AM_(H)17 (SEQ ID NO:43/SEQ ID NO:17);         -   k. a light chain variable domain and a heavy chain variable             domain of AM_(L)19/AM_(H)19 (SEQ ID NO:45/SEQ ID NO:19);         -   l. a light chain variable domain and a heavy chain variable             domain of AM_(L)20/AM_(H)20 (SEQ ID NO:46/SEQ ID NO:20);         -   m. a light chain variable domain and a heavy chain variable             domain of AM_(L)21/AM_(H)21 (SEQ ID NO:47/SEQ ID NO:21);         -   n. a light chain variable domain and a heavy chain variable             domain of AM_(L)22/AM_(H)22 (SEQ ID NO:48/SEQ ID NO:22);         -   o. a light chain variable domain and a heavy chain variable             domain of AM_(L)23/AM_(H)23 (SEQ ID NO:49 or SEQ ID             NO:50/SEQ ID NO:23);         -   p. a light chain variable domain and a heavy chain variable             domain of AM_(L)24/AM_(H)24 (SEQ ID NO:51/SEQ ID NO:24);         -   q. a light chain variable domain and a heavy chain variable             domain of AM_(L)25/AM_(H)25 (SEQ ID NO:52/SEQ ID NO:25);         -   wherein said antibody specifically binds to human IL-17RA.

Embodiment two: the antibody of embodiment 1, wherein said antibody is selected from the group consisting of:

-   -   A. an isolated antibody, or IL-17RA-binding fragment thereof,         comprising         -   a. a light chain variable domain sequence that is at least             80% identical to a light chain variable domain sequence of             AM_(L)9, 14, 16, 17, 19-23v2, and 26 (SEQ ID NOs:35, 40, 42,             43, 45-50, and 53, respectively);         -   b. a heavy chain variable domain sequence that is at least             80% identical to a heavy chain variable domain sequence of             AM_(H)9, 14, 16, 17, 19-23, and 26 (SEQ ID NOs:9, 14, 16,             17, 19-23, and 26, respectively);         -   c. the light chain variable domain of (a) and the heavy             chain variable domain of (b); wherein said antibody             specifically binds to human IL-17RA;     -   B. an isolated antibody, or IL-17RA-binding fragment thereof,         comprising         -   a. a light chain CDR1 (SEQ ID NO:209), CDR2 (SEQ ID NO:210),             CDR3 (SEQ ID NO:211) and a heavy chain CDR1 (SEQ ID NO:131),             CDR2 (SEQ ID NO:132), CDR3 (SEQ ID NO:133) of antibody AM-9;         -   b. a light chain CDR1 (SEQ ID NO:224), CDR2 (SEQ ID NO:225),             CDR3 (SEQ ID NO:226) and a heavy chain CDR1 (SEQ ID NO:146),             CDR2 (SEQ ID NO:147), CDR3 (SEQ ID NO:148) of antibody             AM-14;         -   c. a light chain CDR1 (SEQ ID NO:230), CDR2 (SEQ ID NO:231),             CDR3 (SEQ ID NO:232) and a heavy chain CDR1 (SEQ ID NO:152),             CDR2 (SEQ ID NO:153), CDR3 (SEQ ID NO:154) of antibody             AM-16;         -   d. a light chain CDR1 (SEQ ID NO:233), CDR2 (SEQ ID NO:234),             CDR3 (SEQ ID NO:235) and a heavy chain CDR1 (SEQ ID NO:155),             CDR2 (SEQ ID NO:156), CDR3 (SEQ ID NO:157) of antibody             AM-17;         -   e. a light chain CDR1 (SEQ ID NO:239), CDR2 (SEQ ID NO:240),             CDR3 (SEQ ID NO:241) and a heavy chain CDR1 (SEQ ID NO:161),             CDR2 (SEQ ID NO:162), CDR3 (SEQ ID NO:163) of antibody             AM-19;         -   f. a light chain CDR1 (SEQ ID NO:242), CDR2 (SEQ ID NO:243),             CDR3 (SEQ ID NO:244) and a heavy chain CDR1 (SEQ ID NO:164),             CDR2 (SEQ ID NO:165), CDR3 (SEQ ID NO:166) of antibody             AM-20;         -   g. a light chain CDR1 (SEQ ID NO:245), CDR2 (SEQ ID NO:246),             CDR3 (SEQ ID NO:247) and a heavy chain CDR1 (SEQ ID NO:167),             CDR2 (SEQ ID NO:168), CDR3 (SEQ ID NO:169) of antibody             AM-21;         -   h. a light chain CDR1 (SEQ ID NO:248), CDR2 (SEQ ID NO:249),             CDR3 (SEQ ID NO:250) and a heavy chain CDR1 (SEQ ID NO:170),             CDR2 (SEQ ID NO:171), CDR3 (SEQ ID NO:172) of antibody             AM-22;         -   i. a light chain CDR1 (SEQ ID NO:251), CDR2 (SEQ ID NO:252),             CDR3 (SEQ ID NO:253) and a heavy chain CDR1 (SEQ ID NO:173),             CDR2 (SEQ ID NO:174), CDR3 (SEQ ID NO:175) of antibody             AM-23;         -   j. a light chain CDR1 (SEQ ID NO:254), CDR2 (SEQ ID NO:255),             CDR3 (SEQ ID NO:256) and a heavy chain CDR1 (SEQ ID NO:173),             CDR2 (SEQ ID NO:174), CDR3 (SEQ ID NO:175) of antibody             AM-23;         -   k. a light chain variable domain and a heavy chain variable             domain of AM_(L)26/AM_(H)26 (SEQ ID NO:53/SEQ ID NO:26);         -   wherein said antibody specifically binds to human IL-17RA;             and     -   C. an isolated antibody, or IL-17RA-binding fragment thereof,         comprising         -   a. a light chain variable domain and a heavy chain variable             domain of AM_(L)9/AM_(H)9 (SEQ ID NO:35/SEQ ID NO:9);         -   b. a light chain variable domain and a heavy chain variable             domain of AM_(L)14/AM_(H)14 (SEQ ID NO:40/SEQ ID NO:14);         -   c. a light chain variable domain and a heavy chain variable             domain of AM_(L)16/AM_(H)16 (SEQ ID NO:42/SEQ ID NO:16);         -   d. a light chain variable domain and a heavy chain variable             domain of AM_(L)17/AM_(H)17 (SEQ ID NO:43/SEQ ID NO:17);         -   e. a light chain variable domain and a heavy chain variable             domain of AM_(L)19/AM_(H)19 (SEQ ID NO:45/SEQ ID NO:19);         -   f. a light chain variable domain and a heavy chain variable             domain of AM_(L)20/AM_(H)20 (SEQ ID NO:46/SEQ ID NO:20);         -   g. a light chain variable domain and a heavy chain variable             domain of AM_(L)21/AM_(H)21 (SEQ ID NO:47/SEQ ID NO:21);         -   h. a light chain variable domain and a heavy chain variable             domain of AM_(L)22/AM_(H)22 (SEQ ID NO:48/SEQ ID NO:22);         -   i. a light chain variable domain and a heavy chain variable             domain of AM_(L)23/AM_(H)23 (SEQ ID NO:49 or SEQ ID             NO:50/SEQ ID NO:23);         -   j. a light chain variable domain and a heavy chain variable             domain of AM_(L)26/AM_(H)26 (SEQ ID NO:53/SEQ ID NO:26);         -   wherein said antibody specifically binds to human IL-17RA.

Embodiment three: the antibody of embodiment one, wherein said antibody selected from the group consisting of:

-   -   A. an isolated antibody, or IL-17RA-binding fragment thereof,         comprising         -   a. a light chain variable domain sequence that is at least             80% identical to a light chain variable domain sequence of             AM_(L)12, 14, 16, 17, 19, and 22 (SEQ ID NOs:38, 40, 42, 43,             45, and 48 respectively);         -   b. a heavy chain variable domain sequence that is at least             80% identical to a heavy chain variable domain sequence of             AM_(H)12, 14, 16, 17, 19, and 22 (SEQ ID NOs:12, 14, 16, 17,             19, and 22, respectively);         -   c. the light chain variable domain of (a) and the heavy             chain variable domain of (b); wherein said antibody             specifically binds to human IL-17RA;     -   B. an isolated antibody, or IL-17RA-binding fragment thereof,         comprising         -   a. a light chain CDR1 (SEQ ID NO:218), CDR2 (SEQ ID NO:219),             CDR3 (SEQ ID NO:220) and a heavy chain CDR1 (SEQ ID NO:140),             CDR2 (SEQ ID NO:141), CDR3 (SEQ ID NO:142) of antibody             AM-12;         -   b. a light chain CDR1 (SEQ ID NO:224), CDR2 (SEQ ID NO:225),             CDR3 (SEQ ID NO:226) and a heavy chain CDR1 (SEQ ID NO:146),             CDR2 (SEQ ID NO:147), CDR3 (SEQ ID NO:148) of antibody             AM-14;         -   c. a light chain CDR1 (SEQ ID NO:230), CDR2 (SEQ ID NO:231),             CDR3 (SEQ ID NO:232) and a heavy chain CDR1 (SEQ ID NO:152),             CDR2 (SEQ ID NO:153), CDR3 (SEQ ID NO:154) of antibody             AM-16;         -   d. a light chain CDR1 (SEQ ID NO:233), CDR2 (SEQ ID NO:234),             CDR3 (SEQ ID NO:235) and a heavy chain CDR1 (SEQ ID NO:155),             CDR2 (SEQ ID NO:156), CDR3 (SEQ ID NO:157) of antibody             AM-17;         -   e. a light chain CDR1 (SEQ ID NO:239), CDR2 (SEQ ID NO:240),             CDR3 (SEQ ID NO:241) and a heavy chain CDR1 (SEQ ID NO:161),             CDR2 (SEQ ID NO:162), CDR3 (SEQ ID NO:163) of antibody             AM-19;         -   f. a light chain CDR1 (SEQ ID NO:248), CDR2 (SEQ ID NO:249),             CDR3 (SEQ ID NO:250) and a heavy chain CDR1 (SEQ ID NO:170),             CDR2 (SEQ ID NO:171), CDR3 (SEQ ID NO:172) of antibody             AM-22;         -   wherein said antibody specifically binds to human IL-17RA;             and     -   C. an isolated antibody, or IL-17RA-binding fragment thereof,         comprising         -   a. a light chain variable domain and a heavy chain variable             domain of AM_(L)12/AM_(H)12 (SEQ ID NO:38/SEQ ID NO:12);         -   b. a light chain variable domain and a heavy chain variable             domain of AM_(L)14/AM_(H)14 (SEQ ID NO:40/SEQ ID NO:14);         -   c. a light chain variable domain and a heavy chain variable             domain of AM_(L)16/AM_(H)16 (SEQ ID NO:42/SEQ ID NO:16);         -   d. a light chain variable domain and a heavy chain variable             domain of AM_(L)17/AM_(H)17 (SEQ ID NO:43/SEQ ID NO:17);         -   e. a light chain variable domain and a heavy chain variable             domain of AM_(L)19/AM_(H)19 (SEQ ID NO:45/SEQ ID NO:19);         -   c. a light chain variable domain and a heavy chain variable             domain of AM_(L)22/AM_(H)22 (SEQ ID NO:48/SEQ ID NO:22);         -   wherein said antibody specifically binds to human IL-17RA.

Embodiment four: the antibody of embodiment one, wherein said antibody is selected from the group consisting of:

-   -   A. an isolated antibody, or IL-17RA-binding fragment thereof,         comprising         -   a. a light chain variable domain sequence that is at least             80% identical to a light chain variable domain sequence SEQ             ID NO: 40;         -   b. a heavy chain variable domain sequence that is at least             80% identical to a heavy chain variable domain sequence of             SEQ ID NO:14;         -   c. the light chain variable domain of (a) and the heavy             chain variable domain of (b); wherein said antibody             specifically binds to human IL-17RA;     -   B. an isolated antibody, or IL-17RA-binding fragment thereof,         comprising a light chain CDR1 (SEQ ID NO:224), CDR2 (SEQ ID         NO:225), CDR3 (SEQ ID NO:226) and a heavy chain CDR1 (SEQ ID         NO:146), CDR2 (SEQ ID NO:147), CDR3 (SEQ ID NO:148); wherein         said antibody specifically binds to human IL-17RA; and     -   C. an isolated antibody, or IL-17RA-binding fragment thereof,         comprising a light chain variable domain of SEQ ID NO:40 and a         heavy chain variable domain SEQ ID NO:14; wherein said antibody         specifically binds to human IL-17RA.

Embodiment five: the antibody of embodiment one, wherein said antibody is selected from the group consisting of:

a. a human antibody;

b. a humanized antibody;

c. a chimeric antibody;

d. a monoclonal antibody;

e. an antigen-binding antibody fragment;

f. a single chain antibody;

g. a diabody;

h. a triabody;

i. a tetrabody;

i. a Fab fragment;

k. a F(ab′)2 fragment;

l. an IgD antibody;

m. an IgE antibody;

n. an IgM antibody;

o. an IgG1 antibody;

p. an IgG2 antibody;

q. an IgG3 antibody; and

r. an IgG4 antibody.

Embodiment six: the antibody of embodiment five, wherein said antibody inhibits human IL-17A from binding to human IL-17RA. Embodiment seven: the antibody of embodiment six, wherein said antibody inhibits human IL-17A and IL-17F from binding to human IL-17RA. Embodiment eight: the antibody of embodiment six, wherein said antibody inhibits human IL-17A or IL-17F from binding to human IL-17RA.

Embodiment nine: an isolated monoclonal antibody, or IL-17RA-binding fragment thereof, selected from the group consisting of:

a) a monoclonal antibody that specifically binds human IL-17RA of SEQ ID NO:431 but does not specifically bind to a chimeric polypeptide consisting of SEQ ID NO:434;

b) a monoclonal antibody that specifically binds human IL-17RA of SEQ ID NO:431 but does not specifically bind to a chimeric polypeptide consisting of SEQ ID NO:435; and

c) a monoclonal antibody that specifically binds human IL-17RA of SEQ ID NO:431 but does not specifically bind to a chimeric polypeptide consisting of SEQ ID NO:436.

Embodiment ten: An isolated monoclonal antibody, or IL-17RA-binding fragment thereof, that specifically binds a neutralizing determinant selected from the group consisting of:

a) a polypeptide comprising amino acids 75-96 of SEQ ID NO:431 of human IL-17RA;

b) a polypeptide comprising amino acids 128-154 of SEQ ID NO:431 of human IL-17RA;

c) a polypeptide comprising amino acids 176-197 of SEQ ID NO:431 of human IL-17RA;

d) a polypeptide comprising amino acids 152-297 of SEQ ID NO:431 of human IL-17RA;

e) a polypeptide comprising amino acids 220-284 of SEQ ID NO:431 of human IL-17RA;

f) a polypeptide comprising amino acids 152-198 of SEQ ID NO:431 of human IL-17RA;

g) a polypeptide comprising amino acids 152-186 of SEQ ID NO:431 of human IL-17RA;

h) a polypeptide comprising amino acids 97-297 of SEQ ID NO:431 of human IL-17RA;

i) a polypeptide comprising amino acids 138-270 of SEQ ID NO:431 of human IL-17RA;

j) a polypeptide comprising amino acids 113-198 of SEQ ID NO:431 of human IL-17RA; and

k) a polypeptide comprising amino acids 152-270 of SEQ ID NO:431 of human IL-17RA.

Embodiment eleven: an isolated monoclonal antibody, or IL-17RA-binding fragment thereof, that specifically binds human IL-17RA of SEQ ID NO:431, but does not specifically bind said IL-17RA having any one of the following amino acid substitutions E97R, E113R, S115R, H138R, D152R, D154R, E156R, K166R, Q176R, S177R, D184R, E186R, S198R, H215R, S220R, T228R, T235R, E241R, H243R, L270R, Q284R, or H297R of SEQ ID NO:431. Embodiment twelve: the antibody of embodiment eleven, wherein said antibody specifically binds human IL-17RA of SEQ ID NO:431, but does not specifically bind said IL-17RA having any one of the following amino acid substitutions D152R, D154R, E156R, D184R, E186R, or H297R of SEQ ID NO:431. Embodiment thirteen: the antibody of embodiment eleven, wherein said antibody specifically binds human IL-17RA of SEQ ID NO:431, but does not specifically bind said IL-17RA having the aspartic acid residue at position 152 of SEQ ID NO:431 substituted with an arginine. Embodiment fourteen: the antibody of embodiment eleven, wherein said antibody specifically binds an epitope defined by any one of amino acids D152, D154, E156, D184, E186, or H297 of SEQ ID NO:431.

Embodiment fifteen: the antibody of embodiment fourteen, wherein said antibody specifically binds an epitope defined by at least two of the following amino acids D152, D154, E156, D184, E186, or H297 of SEQ ID NO:431. Embodiment sixteen: the antibody of embodiment fourteen, wherein said antibody specifically binds an epitope defined by at least three of the following amino acids D152, D154, E156, D184, E186, or H297 of SEQ ID NO:431. Embodiment seventeen: the antibody of embodiment fourteen, wherein said antibody specifically binds an epitope defined by at least four of the following amino acids D152, D154, E156, D184, E186, or H297 of SEQ ID NO:431. Embodiment eighteen: the antibody of embodiment fourteen, wherein said antibody specifically binds an epitope defined by at least five of the following amino acids D152, D154, E156, D184, E186, or H297 of SEQ ID NO:431. Embodiment nineteen: the antibody of embodiment fourteen, wherein said antibody specifically binds an epitope defined by amino acids D152, D154, E156, D184, E186, H297 of SEQ ID NO:431.

Embodiment twenty: an isolated monoclonal antibody, or IL-17RA-binding fragment thereof, that specifically binds to IL-17RA and competes for binding with an antibody comprising:

-   -   a. a heavy chain CDR1 comprising an amino acid sequence selected         from the group consisting of:         -   i. X₁YGIS, wherein X₁ is selected from the group consisting             of R, S and G;     -   b. a heavy chain CDR2 comprising an amino acid sequence selected         from the group consisting of:         -   i. WISX₁YX₂GNTX₃YAQX₄X₅QG, wherein X₁ is selected from the             group consisting of A, X₂ is selected from the group             consisting of N, S and K, X₃ is selected from the group             consisting of N and K, X₄ is selected from the group             consisting of K and N, and X₅ is selected from the group             consisting of L and F;     -   c. a heavy chain CDR3 comprising an amino acid sequence selected         from the group consisting of:         -   i. X₁QLX₂X₃DY, wherein X₁ is selected from the group             consisting of R and K, X₂ is selected from the group             consisting of Y, V, and A, and X₃ is selected from the group             consisting of F and L;         -   ii. X₁QLX₂FDY, wherein X₁ is selected from the group             consisting of R and K, and X₂ is selected from the group             consisting of Y and V;     -   d. a light chain CDR1 comprising an amino acid sequence selected         from the group consisting of:         -   i. RASQSX₁X₂X₃X₄LA, wherein X₁ is selected from the group             consisting of V and I, X₂ is selected from the group             consisting of I and S, X₃ is selected from the group             consisting of S and T, X₄ is selected from the group             consisting of N and S, and X₅ is selected from the group             consisting of A and N;         -   ii. RASQSX₁SSNLA, wherein X₁ is selected from the group             consisting of V and I;     -   e. a light chain CDR2 comprising an amino acid sequence selected         from the group consisting of:         -   i. X₁X₂STRAX₃, wherein X₁ is selected from the group             consisting of G and D, X₂ is selected from the group             consisting of A and T, and X₃ is selected from the group             consisting of T and A;         -   ii. X₁ASTRAX₂, wherein X₁ is selected from the group             consisting of G and D, and X₂ is selected from the group             consisting of A and T; and     -   f. a light chain CDR3 comprising an amino acid sequence selected         from the group consisting of:         -   i. QQYDX₁WPLT, wherein X₁ is selected from the group             consisting of N, T, and I.

Embodiment twenty one: the antibody of embodiment twenty, wherein said antibody comprises:

-   -   a. a heavy chain CDR1 amino acid sequence comprising X₁YGIS,         wherein X₁ is selected from the group consisting of R, S and G;     -   b. a heavy chain CDR2 amino acid sequence comprising         WISX₁YX₂GNTX₃YAQX₄X₅QG, wherein X₁ is selected from the group         consisting of A, X₂ is selected from the group consisting of N,         S and K, X₃ is selected from the group consisting of N and K, X₄         is selected from the group consisting of K and N, and X₅ is         selected from the group consisting of L and F;     -   c. a heavy chain CDR3 amino acid sequence comprising X₁QLX₂FDY,         wherein X₁ is selected from the group consisting of R and K, and         X₂ is selected from the group consisting of Y and V;     -   d. a light chain CDR1 amino acid sequence comprising         RASQSX₁SSNLA, wherein X₁ is selected from the group consisting         of V and I;     -   e. a light chain CDR2 amino acid sequence comprising X₁ASTRAX₂,         wherein X₁ is selected from the group consisting of G and D, and         X₂ is selected from the group consisting of A and T; and     -   f. a light chain CDR3 amino acid sequence comprising QQYDX₁WPLT,         wherein X₁ is selected from the group consisting of N, T, and I.

Embodiment twenty two: the antibody of embodiment 20, wherein said antibody is selected from the group consisting of:

a. a human antibody;

b. a humanized antibody;

c. a chimeric antibody;

d. a monoclonal antibody;

e. an antigen-binding antibody fragment;

f. a single chain antibody;

g. a diabody;

h. a triabody;

i. a tetrabody;

j. a Fab fragment;

k. a F(ab′)2 fragment;

l. an IgD antibody;

m. an IgE antibody;

n. an IgM antibody;

o. an IgG1 antibody;

p. an IgG2 antibody;

q. an IgG3 antibody; and

r. an IgG4 antibody.

Embodiment twenty three: the antibody of embodiment twenty two, wherein said antibody inhibits human IL-17A from binding to human IL-17RA. Embodiment twenty four: the antibody of embodiment twenty two, wherein said antibody inhibits human IL-17A and IL-17F from binding to human IL-17RA. Embodiment twenty five: the antibody of embodiment twenty two, wherein said antibody inhibits human IL-17A or IL-17F from binding to human IL-17RA.

IL-17A, IL-17F, and IL-17RA

“IL-17 receptor A” or “IL-17RA” (interchangeably used herein, as well as IL-17 receptor and IL-17R to refer to the same receptor) as used herein is meant the cell surface receptor and receptor complexes (such as but not limited to IL-17RA-IL-17RC complex), that bind IL-17A and IL-17F and as a result initiates a signal transduction pathway within the cell. IL-17RA proteins may also include variants. IL-17RA proteins may also include fragments, such as the extracellular domain that don't have all or part of the transmembrane and/or the intracellular domain, as well as fragments of the extracellular domain. The cloning, characterization, and preparation of IL-17RA are described, for example, in U.S. Pat. No. 6,072,033, which is incorporated herein by reference in its entirety. The amino acid sequence of the human IL-17RA is shown in SEQ ID NO:430. Soluble forms of huIL-17RA useful in the methods of the present invention include the extracellular domain or the mature form lacking the signal peptide or a fragment of the extracellular domain that retains the capacity to bind IL-17A and/or IL-17F, or a heteromeric version of IL-17A and/or IL-17F. Other forms of IL-17RA include muteins and variants that are at least between 70% and 99% homologous to the native IL-17RA of SEQ ID NO:430 and as described in U.S. Pat. No. 6,072,033, so long as the IL-17RA retains the capacity to bind IL-17A and/or IL-17F, or a heteromeric version of IL-17A and/or IL-17F. The term “IL-17RA” also includes post-translational modifications of the IL-17RA amino acid sequence. Post-translational modifications include, but is not limited to, N- and O-linked glycosylation.

IL-17RA Neutralizing Antibodies

Antibodies that specifically bind to human IL-17RA and inhibit IL-17A and/or IL-17F from binding and activating IL-17RA, or a heteromeric complex of IL-17RA and IL-17RC, are disclosed herein. Said antibodies specifically bind to human IL-17RA and may inhibit an IL-17A/IL-17F heteromer from binding and activating IL-17RA, or a heteromeric complex of IL-17RA and IL-17RC. Throughout the specification, when reference is made to inhibiting IL-17A and/or IL-17F, it is understood that this also includes inhibiting heteromers of IL-17A and IL-17F. Said antibodies that specifically bind to human IL-17RA may partially or fully inhibit IL-17RA from forming either a homomeric or heteromeric functional receptor complex, such as, but not limited to, an IL-17RA-IL-17RC complex. Said antibodies may partially or fully inhibit IL-17RA from forming either a homomeric or heteromeric functional receptor complex, such as, but not limited to IL-17RA/IL-17RC complex and do not necessarily inhibit IL-17A and/or IL-17F or an IL-17A/IL-17F heteromer from binding to IL-17RA or a IL-17RA heteromeric receptor complex.

Aspects of the invention include antibodies that compete for binding to human IL-17RA with the aforementioned IL-17RA antibodies. Aspects of the invention include antibodies that bind to the neutralizing determinants described herein. The antibodies that compete for binding to human IL-17RA with the IL-17RA antibodies described herein and the antibodies that bind to the neutralizing determinants described herein will also the same or similar functional attributes described in the previous paragraph. To be clear, antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein, or antibodies that bind to the neutralizing determinants described herein are particular embodiments of the present invention.

The antibodies described herein specifically bind to IL-17RA. “Specifically binds” as used herein means that the antigen binding protein preferentially binds IL-17RA over other proteins. In some embodiments “specifically binds” means that the IL-17RA antigen binding proteins have a higher affinity for IL-17RA than for other proteins. For example, the equilibrium dissociation constant is <10⁻⁷ to 10⁻¹¹ M, or <10⁻⁸ to <10⁻¹⁰ M, or <10⁻⁹ to <10⁻¹⁰ M.

It is understood that when reference is made to the various embodiments of the IL-17RA antibodies, as well as antibodies that compete for binding to human IL-17RA with the IL-17RA neutralizing antibodies described herein, or antibodies that bind to the neutralizing determinants described herein, that it also encompasses IL-17RA-binding fragments thereof. An IL-17RA-binding fragment comprises any of the antibody fragments or domains described herein that retains the ability to specifically bind to IL-17RA. Said IL-17RA-binding fragments may be in any of the scaffolds described herein. Said IL-17RA-binding fragments also have the capacity to inhibit activation of the IL-17RA, as described throughout the specification.

One characteristic of the IL-17RA antibodies described herein, or antibodies that compete for binding with the IL-17RA antibodies described herein, or antibodies that bind to the neutralizing determinants described herein, is that they can inhibit binding of IL-17A and/or IL-17F to IL-17RA and one or more biological activities of, or mediated by, IL-17RA. Such antibodies are considered neutralizing antibodies because of their capacity to inhibit IL-17A and/or IL-17F from binding and causing IL-17RA signaling and/or biological activity. In this case, an IL-17RA neutralizing antibody or antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein, or antibodies that bind to the neutralizing determinants described herein specifically binds IL-17RA and inhibits binding of IL-17A and/or IL-17F to IL-17RA from anywhere between 10 to 100%, such as by at least about 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99% or more (for example by measuring binding in an in vitro competitive binding assay as described herein). An antibody that competes for binding, as described in the examples, is an antibody that inhibits the binding of another antibody to a specific target, which in this case is IL-17RA. Inhibition, in the antibody competition for binding, may be from anywhere between 10 to 100%, such as by at least about 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99% or more (for example by measuring binding in an in vitro competitive binding assay as described herein). For example, IL-17RA antibodies or antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein, or antibodies that bind to the neutralizing determinants described herein may be tested for neutralizing ability by testing them for the production of IL-6 in human foreskin fibroblast (HFF) assay (see for example Examples 4 and 5), or any suitable assay known in the art. Of course, this is just one example of an assay and any suitable assay known in the art may be employed to determine antibodies that fall within the scope of the claims. Further examples, for illustrative purposes only, of additional biological activity of IL-17RA (e.g., assay readouts) to test for inhibition of IL-17RA signaling and/or biological activity include in vitro and/or in vivo measurement of one or more of IL-8, CXCL1, CXCL2, GM-CSF, G-CSF, M-CSF, IL-1□, TNF□, RANK-L, LIF, PGE2, IL-12, MMPs (such as but not limited to MMP3 and MMP9), GRO□, NO, and/or C-telopeptide and the like.

Embodiments of antibodies that compete for binding to human IL-17RA with the IL-17RA neutralizing antibodies described herein, or antibodies that bind to the neutralizing determinants described herein comprise a scaffold structure, as variously define herein, with one or more complementarity determining regions (CDRs). Embodiments of antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein or antibodies that bind to the neutralizing determinants described herein comprise a scaffold structure with one or more variable domains, either heavy or light.

Aspects of the invention include antibodies that compete for binding with the IL-17RA neutralizing antibodies, or antibodies that bind to the neutralizing determinants described herein, wherein said IL-17RA neutralizing antibodies comprise a light chain variable region selected from the group consisting of AM_(L)1 through AM_(L)26 (SEQ ID NO:27-53, respectively, with AM_(L)23 having two versions—SEQ ID NOs:49 and 50) and/or a heavy chain variable region selected from the group consisting of AM_(H)1 through AM_(H)26 (SEQ ID NO:1-26, respectively), as well as human IL-17R-binding fragments, derivatives, muteins, and variants thereof.

Aspects of the invention include antibodies that compete for binding with the IL-17RA neutralizing antibodies, or antibodies that bind to the neutralizing determinants described herein, wherein said IL-17RA neutralizing antibodies comprise variable light and variable heavy domains of: AM_(L)1/AM_(H)1 (SEQ ID NO:27/SEQ ID NO:1), AM_(L)2/AM_(H)2 (SEQ ID NO:28/SEQ ID NO:2), AM_(L)3/AM_(H)3 (SEQ ID NO:29/SEQ ID NO:3), AM_(L)4/AM_(H)4 (SEQ ID NO:30/SEQ ID NO:4), AM_(L)5/AM_(H)5 (SEQ ID NO:31/SEQ ID NO:5), AM_(L)6/AM_(H)6 (SEQ ID NO:32/SEQ ID NO:6), AM_(L)7/AM_(H)7 (SEQ ID NO:33/SEQ ID NO:7), AM_(L)8/AM_(H)8 (SEQ ID NO:34/SEQ ID NO:8), AM_(L)9/AM_(H)9 (SEQ ID NO:35/SEQ ID NO:9), AM_(L)10/AM_(H)10 (SEQ ID NO:36/SEQ ID NO:10), AM_(L)11/AM_(H)11 (SEQ ID NO:37/SEQ ID NO:11), AM_(L)12/AM_(H)12 (SEQ ID NO:38/SEQ ID NO:12), AM_(L)13/AM_(H)13 (SEQ ID NO:39/SEQ ID NO:13), AM_(L)14/AM_(H)14 (SEQ ID NO:40/SEQ ID NO:14), AM_(L)15/AM_(H)15 (SEQ ID NO:41/SEQ ID NO:15), AM_(L)16/AM_(H)16 (SEQ ID NO:42/SEQ ID NO:16), AM_(L)17/AM_(H)17 (SEQ ID NO:43/SEQ ID NO:17), AM_(L)18/AM_(H)18 (SEQ ID NO:44/SEQ ID NO:18), AM_(L)19/AM_(H)19 (SEQ ID NO:45/SEQ ID NO:19), AM_(L)20/AM_(H)20 (SEQ ID NO:46/SEQ ID NO:20), AM_(L)21/AM_(H)21 (SEQ ID NO:47/SEQ ID NO:21), AM_(L)22/AM_(H)22 (SEQ ID NO:48/SEQ ID NO:22), AM_(L)23/AM_(H)23 (SEQ ID NO:49 or SEQ ID NO:50/SEQ ID NO:23), AM_(L)24/AM_(H)24 (SEQ ID NO:51/SEQ ID NO:24), AM_(L)25/AM_(H)25 (SEQ ID NO:52/SEQ ID NO:25), AM_(L)26/AM_(H)26 (SEQ ID NO:53/SEQ ID NO:26), as well as IL-17RA-binding fragments thereof and combinations thereof. Aspects of the invention include antibodies that compete for binding with the IL-17RA neutralizing antibodies, or antibodies that bind to the neutralizing determinants described herein, wherein said IL-17RA neutralizing antibodies comprise, wherein said antibodies specifically bind to human IL-17RA and inhibit IL-17A and/or IL-17F from binding and activating IL-17RA, or a heteromeric complex of IL-17RA and IL-17RC. Further embodiments include antibodies that specifically bind to human IL-17RA and inhibit an IL-17A/IL-17F heteromer from binding and activating IL-17RA, or a heteromeric complex of IL-17RA and IL-17RC. Further embodiments include antibodies that specifically bind to human IL-17RA and partially or fully inhibit IL-17RA from forming either a homomeric or heteromeric functional receptor complex, such as, but not limited to IL-17RA-IL-17RC complex. Further embodiments include antibodies that specifically bind to human IL-17RA and partially or fully inhibit IL-17RA from forming either a homomeric or heteromeric functional receptor complex, such as, but not limited to IL-17RA/IL-17RC complex and do not necessarily inhibit IL-17A and/or IL-17F or an IL-17A/IL-17F heteromer from binding to IL-17RA or a IL-17RA heteromeric receptor complex.

Aspects of the invention include antibodies that compete for binding with the IL-17RA neutralizing antibodies, or antibodies that bind to the neutralizing determinants described herein, wherein said IL-117RA neutralizing antibodies comprise at least one CDR from antibodies comprising AM_(L)1/AM_(H)1 (SEQ ID NO:27/SEQ ID NO:1), AM_(L)2/AM_(H)2 (SEQ ID NO:28/SEQ ID NO:2), AM_(L)3/AM_(H)3 (SEQ ID NO:29/SEQ ID NO:3), AM_(L)4/AM_(H)4 (SEQ ID NO:30/SEQ ID NO:4), AM_(L)5/AM_(H)5 (SEQ ID NO:31/SEQ ID NO:5), AM_(L)6/AM_(H)6 (SEQ ID NO:32/SEQ ID NO:6), AM_(L)7/AM_(H)7 (SEQ ID NO:33/SEQ ID NO:7), AM_(L)8/AM_(H)8 (SEQ ID NO:34/SEQ ID NO:8), AM_(L)9/AM_(H)9 (SEQ ID NO:35/SEQ ID NO:9), AM_(L)10/AM_(H)10 (SEQ ID NO:36/SEQ ID NO:10), AM_(L)11/AM_(H)11 (SEQ ID NO:37/SEQ ID NO:11), AM_(L)12/AM_(H)12 (SEQ ID NO:38/SEQ ID NO:12), AM_(L)13/AM_(H)13 (SEQ ID NO:39/SEQ ID NO:13), AM_(L)14/AM_(H)14 (SEQ ID NO:40/SEQ ID NO:14), AM_(L)15/AM_(H)15 (SEQ ID NO:41/SEQ ID NO:15), AM_(L)16/AM_(H)16 (SEQ ID NO:42/SEQ ID NO:16), AM_(L)17/AM_(H)17 (SEQ ID NO:43/SEQ ID NO:17), AM_(L)18/AM_(H)18 (SEQ ID NO:44/SEQ ID NO:18), AM_(L)19/AM_(H)19 (SEQ ID NO:45/SEQ ID NO:19), AM_(L)20/AM_(H)20 (SEQ ID NO:46/SEQ ID NO:20), AM_(L)21/AM_(H)21 (SEQ ID NO:47/SEQ ID NO:21), AM_(L)22/AM_(H)22 (SEQ ID NO:48/SEQ ID NO:22), AM_(L)23/AM_(H)23 (SEQ ID NO:49 or SEQ ID NO:50/SEQ ID NO:23), AM_(L)24/AM_(H)24 (SEQ ID NO:51/SEQ ID NO:24), AM_(L)25/AM_(H)25 (SEQ ID NO:52/SEQ ID NO:25), AM_(L)26/AM_(H)26 (SEQ ID NO:53/SEQ ID NO:26), as well as IL-17RA-binding fragments thereof and combinations thereof. See Table 1.

Aspects of the invention include antibodies that compete for binding with the IL-17RA neutralizing antibodies, or antibodies that bind to the neutralizing determinants described herein, wherein said IL-17RA neutralizing antibodies comprise at least one, two, or three H-CDR regions of any of SEQ ID NOs:107-184 and at least one, two, or three L-CDR region of any of SEQ ID NOs:185-265. See Table 1.

Examples 8-11 describe various studies elucidating domains on human IL-17RA that neutralizing IL-17RA mAbs bound. These domains are referred to as neutralizing determinants. A neutralizing determinant is a contiguous stretch of IL-17RA, that when mutated, negatively affects the binding of at least one of the neutralizing antibodies disclosed herein. A neutralizing determinant comprises at least one epitope. A neutralizing determinant may have primary, secondary, tertiary, and/or quarternary structural characteristics. A neutralizing antibody is any of the antibodies described herein that specifically binds human IL-17RA and inhibits binding of IL-17A and/or IL-17F and thereby inhibits IL-17RA signaling and/or biological activity. In addition, a neutralizing antibody encompasses antibodies that compete for binding to human IL-17RA with the IL-17RA antibodies described herein, as well as antibodies that bind to the neutralizing determinants described herein.

FIGS. 8A and 8B show that antibodies A: AM_(H)11/AM_(L)11, B: AM_(H)4/AM_(L)4, C: AM_(H)8/AM_(L)8, D: AM_(H)7/AM_(L)7, E: AM_(H)6/AM_(L)6, F: AM_(H)10/AM_(L)10, and G: AM_(H)18/AM_(L)18 competed with one another for binding to human IL-17RA and fell into a defined group (Bin 1). In general, antibodies I: AM_(H)22/AM_(L)22, J: AM_(H)23/AM_(L)23, K: AM_(H)14/AM_(L)14, L: AM_(H)19/AM_(L)19, M: AM_(H)12/AM_(L)12, N: AM_(H)17/AM_(L)17, O: AM_(H)16/AM_(L)16 competed with one another for binding to human IL-17RA and as a consequence fell into a different group (Bin 3). Generally speaking, the antibodies of Bin 1 did not compete with the antibodies of Bin 3. Antibody H: AM_(H)1/AM_(L)1 was unique in its competition pattern and formed Bin 2, but is most similar to Bin 3. Antibody P: AM_(H)26/AM_(L)26 formed Bin 4 and showed little cross-competition with any of the other antibodies, suggesting a neutralizing determinant unique to this antibody. Antibodies Q: AM_(H)21/AM_(L)21 and R: AM_(H)20/AM_(L)20 showed individually unique competition patterns, but with considerable similarities to Bin 3 antibodies, and formed Bins 5 and 6, respectively. This method identified groups of antibodies binding to different neutralizing determinants and provides evidence of several species within a subgenus of cross-competing antibodies.

Example 10 describes the use of human/mouse IL-17RA chimeric proteins to determine neutralizing determinants on human IL-17RA. FIG. 11 show that at least three neutralizing determinants were identified based on those regions affecting the binding of neutralizing IL-17RA antibodies, namely neutralizing determinant B spanning amino acids 75-96 of human IL-17RA (SEQ ID NO:431), neutralizing determinant C spanning amino acids 128-154 of human IL-17RA (SEQ ID NO:431), and neutralizing determinant D spanning amino acids 176-197 of human IL-17RA (SEQ ID NO:431). Neutralizing determinant B spanning amino acids 75-96 of human IL-17RA (SEQ ID NO:431) negatively affected the binding of neutralizing antibodies AM_(H)1/AM_(L)1 and AM_(H)23/AM_(L)23. Neutralizing determinant C spanning amino acids 128-154 of human IL-17RA (SEQ ID NO:431) negatively affected the binding of neutralizing antibodies AM_(H)22/AM_(L)22 and AM_(H)23/AM_(L)23. Neutralizing determinant D spanning amino acids 176-197 of human IL-17RA (SEQ ID NO:431) negatively affected the binding of neutralizing antibodies AM_(H)1/AM_(L)1, AM_(H)22/AM_(L)22, AM_(H)14/AM_(L)14, AM_(H)19/AM_(L)19, AM_(H)23/AM_(L)23, AM_(H)21/AM_(L)21, and AM_(H)20/AM_(L)20. Thus, neutralizing determinants B, C, and D are all considered neutralizing determinants.

Example 11 describes the use of arginine scan techniques to further elucidate the domains on human IL-17R that the IL-17RA neutralizing antibodies bound. A summary of the arginine scan, binning, and chimera data is presented in FIG. 11. The arginine scan methodology identified several neutralizing determinants: AM_(H)18/AM_(L)18 bound a domain spanning amino acids 220-284 of human IL-17RA (SEQ ID NO:431); AM_(H)1/AM_(L)1 bound a domain focused on amino acid residue 152 of human IL-17RA (SEQ ID NO:431); AM_(H)22/AM_(L)22 bound a domain spanning amino acids 152-198 of human IL-17RA (SEQ ID NO:431); AM_(H)14/AM_(L)14 bound a domain spanning amino acids 152-297 of human IL-17RA (SEQ ID NO:431); AM_(H)19/AM_(L)19 bound a domain spanning amino acids 152-186 of human IL-17RA (SEQ ID NO:431); AM_(H)23/AM_(L)23 bound a domain spanning amino acids 97-297 of human IL-17RA (SEQ ID NO:431); AM_(H)26/AM_(L)26 bound a domain spanning amino acids 138-270 of human IL-17RA (SEQ ID NO:431); AM_(H)21/AM_(L)21 bound a domain spanning amino acids 113-198 of human IL-17RA (SEQ ID NO:431); and AM_(H)20/AM_(L)20 bound a domain spanning amino acids 152-270 of human IL-17RA (SEQ ID NO:431). All of the residues shown in FIG. 14 have been shown to significantly reduce or essentially eliminate binding of a neutralizing human monoclonal antibody that specifically binds to human IL-17RA.

Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds to IL-17RA and competes for binding with any one of antibodies AM_(H)3/AM_(L)3, AM_(H)20/AM_(L)20, AM_(H)22/AM_(L)22, AM_(H)23/AM_(L)23, AM_(H)14/AM_(L)14, AM_(H)21/AM_(L)21, AM_(H)19/AM_(L)19, AM_(H)12/AM_(L)12, AM_(H)17/AM_(L)17, or AM_(H)16/AM_(L)16, or any subset therein.

Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds to IL-17R and competes for binding with any one of antibodies AM_(H)22/AM_(L)22, AM_(H)23/AM_(L)23, AM_(H)14/AM_(L)14, AM_(H)19/AM_(L)19, AM_(H)12/AM_(L)12, AM_(H)17/AM_(L)17, or AM_(H)16/AM_(L)16, or any subset therein.

Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds human IL-17RA of SEQ ID NO:431 but does not specifically bind to a chimeric polypeptide consisting of SEQ ID NO:434. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds human IL-17RA of SEQ ID NO:431 but does not specifically bind to a chimeric polypeptide consisting of SEQ ID NO:435. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds human IL-17RA of SEQ ID NO:431 but does not specifically bind to a chimeric polypeptide consisting of SEQ ID NO:436.

Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds a neutralizing determinant comprising amino acids 75-96 of SEQ ID NO:431 of human IL-17RA. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds a neutralizing determinant comprising amino acids 128-154 of SEQ ID NO:431 of human IL-17RA. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds a neutralizing determinant comprising amino acids 176-197 of SEQ ID NO:431 of human IL-17RA. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds a neutralizing determinant comprising amino acids 152-297 of SEQ ID NO:431 of human IL-17RA. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds a neutralizing determinant comprising amino acids 220-284 of SEQ ID NO:431 of human IL-17RA. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds a neutralizing determinant comprising amino acids 152-198 of SEQ ID NO:431 of human IL-17RA. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds a neutralizing determinant comprising amino acids 152-186 of SEQ ID NO:431 of human IL-17RA. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds a neutralizing determinant comprising amino acids 97-297 of SEQ ID NO:431 of human IL-17RA. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds a neutralizing determinant comprising amino acids 138-270 of SEQ ID NO:431 of human IL-17RA. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds a neutralizing determinant comprising amino acids 113-198 of SEQ ID NO:431 of human IL-17RA. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds a neutralizing determinant comprising amino acids 152-270 of SEQ ID NO:431 of human IL-17RA.

Further embodiments include an antibody, or IL-17RA-binding fragment thereof, that binds human IL-17RA of SEQ ID NO:431, but does not bind said IL-17RA having an amino acid substituted with arginine at any one of E97R, E113R, S115R, H138R, D152R, D154R, E156R, K166R, Q176R, S177R, D184R, E186R, S198R, H215R, S220R, T228R, T235R, E241R, H243R, L270R, Q284R, H297R of SEQ ID NO:431. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that binds human IL-17RA of SEQ ID NO:431, but does not bind said IL-17RA having an amino acid substituted with arginine at any one of D152R, D154R, E156R, D184R, E186R, H297R of SEQ ID NO:431. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that binds human IL-17RA of SEQ ID NO:431, but does not bind said IL-17RA having an amino acid substituted with arginine at D152R of SEQ ID NO:431.

Further embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds an epitope defined by any one of amino acids D152, D154, E156, D184, E186, H297 of SEQ ID NO:431. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds an epitope defined by at least two amino acids selected from the group consisting of: D152, D154, E156, D184, E186, H297 of SEQ ID NO:431. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds an epitope defined by at least three amino acids selected from the group consisting of: D152, D154, E156, D184, E186, H297 of SEQ ID NO:431. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds an epitope defined by at least four amino acids selected from the group consisting of: D152, D154, E156, D184, E186, H297 of SEQ ID NO:431. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds an epitope defined by at least five amino acids selected from the group consisting of: D152, D154, E156, D184, E186, H297 of SEQ ID NO:431. Embodiments include an antibody, or IL-17RA-binding fragment thereof, that specifically binds an epitope defined by amino acids D152, D154, E156, D184, E186, H297 of SEQ ID NO:431.

The antibodies of the invention include scaffold regions and one or more CDRs: between one and six CDRs (as typically do naturally occurring antibodies), for example, one heavy chain CDR1 (“H-CDR1”), and/or one heavy chain CDR2 (“H-CDR2”), and/or one heavy chain CDR3 (“H-CDR3”), and/or one light chain CDR1 (“L-CDR1”), and/or one light chain CDR2 (“L-CDR2”), and/or one light chain CDR3 (“L-CDR3”).

The term “naturally occurring” as used throughout the specification in connection with biological materials such as peptides, polypeptides, nucleic acids, host cells, and the like, refers to materials which are found in nature. In naturally occurring antibodies, a H-CDR1 typically comprises about five (5) to about seven (7) amino acids, H-CDR2 typically comprises about sixteen (16) to about nineteen (19) amino acids, and H-CDR3 typically comprises about three (3) to about twenty five (25) amino acids. L-CDR1 typically comprises about ten (10) to about seventeen (17) amino acids, L-CDR2 typically comprises about seven (7) amino acids, and L-CDR3 typically comprises about seven (7) to about ten (10) amino acids. Specific CDRs of the IL-17RA neutralizing antibodies are provided in TABLE I and the Sequence Listing.

TABLE 1 Corresponding Polynucleotide Sequence Amino acid SEQ ID NYYWN SEQ ID NO:266 sequence of NO:107 CDR 1 of AM_(H)1 Vh Amino acid SEQ ID DIYYSGSTNYNPS SEQ ID NO:267 sequence of NO:108 LKS CDR 2 of AM_(H)1 Vh Amino acid SEQ ID DGELANYYGSGS SEQ ID NO:268 sequence of NO:109 YQFYYYYGMDV CDR 3 of AM_(H)1 Vh Amino acid SEQ ID GYYWS SEQ ID NO:269 sequence of NO:110 CDR 1 of AM_(H)2 Vh Amino acid SEQ ID EINHSGRTNYNPS SEQ ID NO:270 sequence of NO:111 LKS CDR 2 of AM_(H)2 Vh Amino acid SEQ ID GPYYFDSSGYLYY SEQ ID NO:271 sequence of NO:112 YYGLDV CDR 3 of AM_(H)2 Vh Amino acid SEQ ID SYGMH SEQ ID NO:272 sequence of NO:113 CDR 1 of AM_(H)3 Vh Amino acid SEQ ID VIWYDGSNKHYA SEQ ID NO:273 sequence of NO:114 DSVKG CDR 2 of AM_(H)3 Vh Amino acid SEQ ID DTGVY SEQ ID NO:274 sequence of NO:115 CDR 3 of AM_(H)3 Vh Amino acid SEQ ID SYGMH SEQ ID NO:275 sequence of NO:116 CDR 1 of AM_(H)4 Vh Amino acid SEQ ID VIWYDGSNKHYA SEQ ID NO:276 sequence of NO:117 DSVKG CDR 2 of AM_(H)4 Vh Amino acid SEQ ID DTGVY SEQ ID NO:277 sequence of NO:118 CDR 3 of AM_(H)4 Vh Amino acid SEQ ID SYYWS SEQ ID NO:278 sequence of NO:119 CDR 1 of AM_(H)5 Vh Amino acid SEQ ID RIYRSGNTIYNPSL SEQ ID NO:279 sequence of NO:120 KS CDR 2 of AM_(H)5 Vh Amino acid SEQ ID ENYSESSGLYYYY SEQ ID NO:280 sequence of NO:121 GMDV CDR 3 of AM_(H)5 Vh Amino acid SEQ ID RYGIS SEQ ID NO:281 sequence of NO:122 CDR 1 of AM_(H)6 Vh Amino acid SEQ ID WISAYNGNTNYA SEQ ID NO:282 sequence of NO:123 QKLQG CDR 2 of AM_(H)6 Vh Amino acid SEQ ID RDYDILTGYYNGF SEQ ID NO:283 sequence of NO:124 DP CDR 3 of AM_(H)6 Vh Amino acid SEQ ID RYGIS SEQ ID NO:284 sequence of NO:125 CDR 1 of AM_(H)7 Vh Amino acid SEQ ID WISAYNGNTNYA SEQ ID NO:285 sequence of NO:126 QKLQG CDR 2 of AM_(H)7 Vh Amino acid SEQ ID RDYDILTGYYNGF SEQ ID NO:286 sequence of NO:127 DP CDR 3 of AM_(H)7 Vh Amino acid SEQ ID GYGIS SEQ ID NO:287 sequence of NO:128 CDR 1 of AM_(H)8 Vh Amino acid SEQ ID WISAYNGNTNYA SEQ ID NO:288 sequence of NO:129 QNLQG CDR 2 of AM_(H)8 Vh Amino acid SEQ ID RDYDILTGYYNGF SEQ ID NO:289 sequence of NO:130 DP CDR 3 of AM_(H)8 Vh Amino acid SEQ ID RYGIS SEQ ID NO:290 sequence of NO:131 CDR 1 of AM_(H)9 Vh Amino acid SEQ ID WISAYNGNTNYA SEQ ID NO:291 sequence of NO:132 QKLQG CDR 2 of AM_(H)9 Vh Amino acid SEQ ID RDYDILTGYYNGF SEQ ID NO:292 sequence of NO:133 DP CDR 3 of AM_(H)9 Vh Amino acid SEQ ID SGGYYWS SEQ ID NO:293 sequence of NO:134 CDR 1 of AM_(H)10 Vh Amino acid SEQ ID YIYFSGSAYYNPS SEQ ID NO:294 sequence of NO:135 LKS CDR 2 of AM_(H)10 Vh Amino acid SEQ ID EYYDSSGYPDAFD SEQ ID NO:295 sequence of NO:136 I CDR 3 of AM_(H)10 Vh Amino acid SEQ ID SYGMH SEQ ID NO:296 sequence of NO:137 CDR 1 of AM_(H)11 Vh Amino acid SEQ ID VIWYDGSNKYYA SEQ ID NO:297 sequence of NO:138 DSVKG CDR 2 of AM_(H)11 Vh Amino acid SEQ ID DTKDY SEQ ID NO:298 sequence of NO:139 CDR 3 of AM_(H)11 Vh Amino acid SEQ ID SYGIS SEQ ID NO:299 sequence of NO:140 CDR 1 of AM_(H)12 Vh Amino acid SEQ ID WISTYKGNTNYA SEQ ID NO:300 sequence of NO:141 QKLQG CDR 2 of AM_(H)12 Vh Amino acid SEQ ID KQLVFDY SEQ ID NO:301 sequence of NO:142 CDR 3 of AM_(H)12 Vh Amino acid SEQ ID SYGMQ SEQ ID NO:302 sequence of NO:143 CDR 1 of AM_(H)13 Vh Amino acid SEQ ID VIWYDGNKKYYA SEQ ID NO:303 sequence of NO:144 DSVKG CDR 2 of AM_(H)13 Vh Amino acid SEQ ID GRVRDYYYGMD SEQ ID NO:304 sequence of NO:145 V CDR 3 of AM_(H)13 Vh Amino acid SEQ ID RYGIS SEQ ID NO:305 sequence of NO:146 CDR 1 of AM_(H)14 Vh Amino acid SEQ ID WISTYSGNTNYA SEQ ID NO:306 sequence of NO:147 QKLQG CDR 2 of AM_(H)14 Vh Amino acid SEQ ID RQLYFDY SEQ ID NO:307 sequence of NO:148 CDR 3 of AM_(H)14 Vh Amino acid SEQ ID SYGMQ SEQ ID NO:308 sequence of NO:149 CDR 1 of AM_(H)15 Vh Amino acid SEQ ID VIWYDGNKKYYA SEQ ID NO:309 sequence of NO:150 DSVKG CDR 2 of AM_(H)15 Vh Amino acid SEQ ID GRVRDYYYGMD SEQ ID NO:310 sequence of NO:151 V CDR 3 of AM_(H)15 Vh Amino acid SEQ ID SYGIS SEQ ID NO:311 sequence of NO:152 CDR 1 of AM_(H)16 Vh Amino acid SEQ ID WISAYNGNTKYA SEQ ID NO:312 sequence of NO:153 QKLQG CDR 2 of AM_(H)16 Vh Amino acid SEQ ID KQLVFDY SEQ ID NO:313 sequence of NO:154 CDR 3 of AM_(H)16 Vh Amino acid SEQ ID SYGIS SEQ ID NO:314 sequence of NO:155 CDR 1 of AM_(H)17 Vh Amino acid SEQ ID WISAYSGNTKYA SEQ ID NO:315 sequence of NO:156 QKLQG CDR 2 of AM_(H)17 Vh Amino acid SEQ ID KQLVFDY SEQ ID NO:316 sequence of NO:157 CDR 3 of AM_(H)17 Vh Amino acid SEQ ID DYYMH SEQ ID NO:317 sequence of NO:158 CDR 1 of AM_(H)18 Vh Amino acid SEQ ID WMHPNSGGTDLA SEQ ID NO:318 sequence of NO:159 QRFQG CDR 2 of AM_(H)18 Vh Amino acid SEQ ID GGYCSTLSCSFYW SEQ ID NO:319 sequence of NO:160 YFDL CDR 3 of AM_(H)18 Vh Amino acid SEQ ID SYGIS SEQ ID NO:320 sequence of NO:161 CDR 1 of AM_(H)19 Vh Amino acid SEQ ID WISAYSGNTKYA SEQ ID NO:321 sequence of NO:162 QKFQG CDR 2 of AM_(H)19 Vh Amino acid SEQ ID RQLALDY SEQ ID NO:322 sequence of NO:163 CDR 3 of AM_(H)19 Vh Amino acid SEQ ID SYSMN SEQ ID NO:323 sequence of NO:164 CDR 1 of AM_(H)20 Vh Amino acid SEQ ID FISARSSTIYYADS SEQ ID NO:324 sequence of NO:165 VKG CDR 2 of AM_(H)20 Vh Amino acid SEQ ID PKVGGGMDV SEQ ID NO:325 sequence of NO:166 CDR 3 of AM_(H)20 Vh Amino acid SEQ ID SYSMN SEQ ID NO:326 sequence of NO:167 CDR 1 of AM_(H)21 Vh Amino acid SEQ ID IISSRSSIIHYADSV SEQ ID NO:327 sequence of NO:168 KG CDR 2 of AM_(H)21 Vh Amino acid SEQ ID PKVGGGMDV SEQ ID NO:328 sequence of NO:169 CDR 3 of AM_(H)21 Vh Amino acid SEQ ID RYGIS SEQ ID NO:329 sequence of NO:170 CDR 1 of AM_(H)22 Vh Amino acid SEQ ID WISAYSGNTNYA SEQ ID NO:330 sequence of NO:171 QKLQG CDR 2 of AM_(H)22 Vh Amino acid SEQ ID RQLYFDY SEQ ID NO:331 sequence of NO:172 CDR 3 of AM_(H)22 Vh Amino acid SEQ ID SYYWS SEQ ID NO:332 sequence of NO:173 CDR 1 of AM_(H)23 Vh Amino acid SEQ ID RIYPSGRTNYNPS SEQ ID NO:333 sequence of NO:174 LKS CDR 2 of AM_(H)23 Vh Amino acid SEQ ID EAYELQLGLYYY SEQ ID NO:334 sequence of NO:175 YGMDV CDR 3 of AM_(H)23 Vh Amino acid SEQ ID SYYWS SEQ ID NO:335 sequence of NO:176 CDR 1 of AM_(H)24 Vh Amino acid SEQ ID RIYPSGRTNYNPS SEQ ID NO:336 sequence of NO:177 LKS CDR 2 of AM_(H)24 Vh Amino acid SEQ ID EAYELQLGLYYY SEQ ID NO:337 sequence of NO:178 YGMDV CDR 3 of AM_(H)24 Vh Amino acid SEQ ID SGGYYWS SEQ ID NO:338 sequence of NO:179 CDR 1 of AM_(H)25 Vh Amino acid SEQ ID YSGNTYYNPSLRS SEQ ID NO:339 sequence of NO:180 CDR 2 of AM_(H)25 Vh Amino acid SEQ ID EAGGNSAYYYGM SEQ ID NO:340 sequence of NO:181 DV CDR 3 of AM_(H)25 Vh Amino acid SEQ ID DYYMS SEQ ID NO:341 sequence of NO:182 CDR 1 of AM_(H)26 Vh Amino acid SEQ ID YISSSGSTIYYADS SEQ ID NO:342 sequence of NO:183 VKG CDR 2 of AM_(H)26 Vh Amino acid SEQ ID DRTYYFGSGSYEG SEQ ID NO:343 sequence of NO:184 MDV CDR 3 of AM_(H)26 Vh Amino acid SEQ ID RASQGIRNDLG SEQ ID NO:345 sequence of NO:185 CDR 1 of AM_(L)1 Vl Amino acid SEQ ID AASSLQS SEQ ID NO:346 sequence of NO:186 CDR 2 of AM_(L)1 Vl Amino acid SEQ ID LQHNSNPFT SEQ ID NO:347 sequence of NO:187 CDR 3 of AM_(L)1 Vl Amino acid SEQ ID RASQSVSRNLV SEQ ID NO:348 sequence of NO:188 CDR 1 of AM_(L)2 Vl Amino acid SEQ ID GASTRAN SEQ ID NO:349 sequence of NO:189 CDR 2 of AM_(L)2 Vl Amino acid SEQ ID QQYKSWRT SEQ ID NO:350 sequence of NO:190 CDR 3 of AM_(L)2 Vl Amino acid SEQ ID RASQSISSYLN SEQ ID NO:351 sequence of NO:191 CDR 1 of AM_(L)3 Vl Amino acid SEQ ID AASSLQS SEQ ID NO:352 sequence of NO:192 CDR 2 of AM_(L)3 Vl Amino acid SEQ ID QQSYSTPFT SEQ ID NO:353 sequence of NO:193 CDR 3 of AM_(L)3 Vl Amino acid SEQ ID RASQSVSRNLA SEQ ID NO:354 sequence of NO:194 CDR 1 of AM_(L)4 Vl Amino acid SEQ ID GASTRAT SEQ ID NO:355 sequence of NO:195 CDR 2 of AM_(L)4 Vl Amino acid SEQ ID QQYNNWPTWT SEQ ID NO:356 sequence of NO:196 CDR 3 of AM_(L)4 Vl Amino acid SEQ ID RASQGIRNDLG SEQ ID NO:357 sequence of NO:197 CDR 1 of AM_(L)5 Vl Amino acid SEQ ID AASSFQS SEQ ID NO:358 sequence of NO:198 CDR 2 of AM_(L)5 Vl Amino acid SEQ ID LQHNSYPPT SEQ ID NO:359 sequence of NO:199 CDR 3 of AM_(L)5 Vl Amino acid SEQ ID RASQGIRNDLG SEQ ID NO:360 sequence of NO:200 CDR 1 of AM_(L)6 Vl Amino acid SEQ ID AASSLQS SEQ ID NO:361 sequence of NO:201 CDR 2 of AM_(L)6 Vl Amino acid SEQ ID LQHKSYPLT SEQ ID NO:362 sequence of NO:202 CDR 3 of AM_(L)6 Vl Amino acid SEQ ID RASQGIRNDLG SEQ ID NO:363 sequence of NO:203 CDR 1 of AM_(L)7 Vl Amino acid SEQ ID AASSLQS SEQ ID NO:364 sequence of NO:204 CDR 2 of AM_(L)7 Vl Amino acid SEQ ID LQHKSYPLT SEQ ID NO:365 sequence of NO:205 CDR 3 of AM_(L)7 Vl Amino acid SEQ ID RASQGIRNDLG SEQ ID NO:366 sequence of NO:206 CDR 1 of AM_(L)8 Vl Amino acid SEQ ID AASSLQS SEQ ID NO:367 sequence of NO:207 CDR 2 of AM_(L)8 Vl Amino acid SEQ ID LQHKSYPLT SEQ ID NO:368 sequence of NO:208 CDR 3 of AM_(L)8 Vl Amino acid SEQ ID RASQGIRNDLG SEQ ID NO:369 sequence of NO:209 CDR 1 of AM_(L)9 Vl Amino acid SEQ ID AASSLQS SEQ ID NO:370 sequence of NO:210 CDR 2 of AM_(L)9 Vl Amino acid SEQ ID LQHKSYPLT SEQ ID NO:371 sequence of NO:211 CDR 3 of AM_(L)9 Vl Amino acid SEQ ID RASQGIRSWLA SEQ ID NO:372 sequence of NO:212 CDR 1 of AM_(L)10 Vl Amino acid SEQ ID AASSLQS SEQ ID NO:373 sequence of NO:213 CDR 2 of AM_(L)10 Vl Amino acid SEQ ID QQANNFPRT SEQ ID NO:374 sequence of NO:214 CDR 3 of AM_(L)10 Vl Amino acid SEQ ID RASQSVSSNLA SEQ ID NO:375 sequence of NO:215 CDR 1 of AM_(L)11 Vl Amino acid SEQ ID GASTRAA SEQ ID NO:376 sequence of NO:216 CDR 2 of AM_(L)11 Vl Amino acid SEQ ID QHYINWPKWT SEQ ID NO:377 sequence of NO:217 CDR 3 of AM_(L)11 Vl Amino acid SEQ ID RASQSISSSLA SEQ ID NO:378 sequence of NO:218 CDR 1 of AM_(L)12 Vl Amino acid SEQ ID GASTRAT SEQ ID NO:379 sequence of NO:219 CDR 2 of AM_(L)12 Vl Amino acid SEQ ID QQYDNWPLT SEQ ID NO:380 sequence of NO:220 CDR 3 of AM_(L)12 Vl Amino acid SEQ ID KSSQSLLHSDGKT SEQ ID NO:381 sequence of NO:221 YLY CDR 1 of AM_(L)13 Vl Amino acid SEQ ID EVSTRFS SEQ ID NO:382 sequence of NO:222 CDR 2 of AM_(L)13 Vl Amino acid SEQ ID MQSIQLPLT SEQ ID NO:383 sequence of NO:223 CDR 3 of AM_(L)13 Vl Amino acid SEQ ID RASQSVSSNLA SEQ ID NO:384 sequence of NO:224 CDR 1 of AM_(L)14 Vl Amino acid SEQ ID DASTRAT SEQ ID NO:385 sequence of NO:225 CDR 2 of AM_(L)14 Vl Amino acid SEQ ID QQYDNWPLT SEQ ID NO:386 sequence of NO:226 CDR 3 of AM_(L)14 Vl Amino acid SEQ ID RASQSVSSNLA SEQ ID NO:387 sequence of NO:227 CDR 1 of AM_(L)15 Vl Amino acid SEQ ID DASTRAA SEQ ID NO:388 sequence of NO:228 CDR 2 of AM_(L)15 Vl Amino acid SEQ ID QQYDNWPLT SEQ ID NO:389 sequence of NO:229 CDR 3 of AM_(L)15 Vl Amino acid SEQ ID RASQSISTSLA SEQ ID NO:390 sequence of NO:230 CDR 1 of AM_(L)16 Vl Amino acid SEQ ID GTSTRAT SEQ ID NO:391 sequence of NO:231 CDR 2 of AM_(L)16 Vl Amino acid SEQ ID QQYDIWPLT SEQ ID NO:392 sequence of NO:232 CDR 3 of AM_(L)16 Vl Amino acid SEQ ID RASQSVSSNLA SEQ ID NO:393 sequence of NO:233 CDR 1 of AM_(L)17 Vl Amino acid SEQ ID GASTRAT SEQ ID NO:394 sequence of NO:234 CDR 2 of AM_(L)17 Vl Amino acid SEQ ID QQYDNWPLT SEQ ID NO:395 sequence of NO:235 CDR 3 of AM_(L)17 Vl Amino acid SEQ ID KTSQSVLYSSKNK SEQ ID NO:396 sequence of NO:236 NFLA CDR 1 of AM_(L)18 Vl Amino acid SEQ ID WASTRES SEQ ID NO:397 sequence of NO:237 CDR 2 of AM_(L)18 Vl Amino acid SEQ ID QQYYSTPFT SEQ ID NO:398 sequence of NO:238 CDR 3 of AM_(L)18 Vl Amino acid SEQ ID RASQSISSNLA SEQ ID NO:399 sequence of NO:239 CDR 1 of AM_(L)19 Vl Amino acid SEQ ID GASTRAT SEQ ID NO:400 sequence of NO:240 CDR 2 of AM_(L)19 Vl Amino acid SEQ ID QQYDTWPLT SEQ ID NO:401 sequence of NO:241 CDR 3 of AM_(L)19 Vl Amino acid SEQ ID RASQGISNYLA SEQ ID NO:402 sequence of NO:242 CDR 1 of AM_(L)20 Vl Amino acid SEQ ID AASTLQS SEQ ID NO:403 sequence of NO:243 CDR 2 of AM_(L)20 Vl Amino acid SEQ ID QKYNRAPFT SEQ ID NO:404 sequence of NO:244 CDR 3 of AM_(L)20 Vl Amino acid SEQ ID RASQGISNYLA SEQ ID NO:405 sequence of NO:245 CDR 1 of AM_(L)21 Vl Amino acid SEQ ID AASTLQS SEQ ID NO:406 sequence of NO:246 CDR 2 of AM_(L)21 Vl Amino acid SEQ ID QKYNRAPFT SEQ ID NO:407 sequence of NO:247 CDR 3 of AM_(L)21 Vl Amino acid SEQ ID RASQSVSSNLA SEQ ID NO:408 sequence of NO:248 CDR 1 of AM_(L)22 Vl Amino acid SEQ ID DASTRAA SEQ ID NO:409 sequence of NO:249 CDR 2 of AM_(L)22 Vl Amino acid SEQ ID QQYDNWPLT SEQ ID NO:410 sequence of NO:250 CDR 3 of AM_(L)22 Vl Amino acid SEQ ID RASQGIINDLG SEQ ID NO:411 sequence of NO:251 CDR 1 of AM_(L)23 Vl version 1 Amino acid SEQ ID AASSLQS SEQ ID NO:412 sequence of NO:252 CDR 2 of AM_(L)23 Vl version 1 Amino acid SEQ ID LQHNSYPPT SEQ ID NO:413 sequence of NO:253 CDR 3 of AM_(L)23 Vl version 1 Amino acid SEQ ID RSSQSLVYSDGHT SEQ ID NO:414 sequence of NO:254 CLN CDR 1 of AM_(L)23 Vl version 2 Amino acid SEQ ID KVSNWDS SEQ ID NO:415 sequence of NO:255 CDR 2 of AM_(L)23 Vl version 2 Amino acid SEQ ID MQGTHWPLCS SEQ ID NO:416 sequence of NO:256 CDR 3 of AM_(L)23 Vl version 2 Amino acid SEQ ID RSSQSLVYSDGHT SEQ ID NO:417 sequence of NO:257 CLN CDR 1 of AM_(L)24 Vl Amino acid SEQ ID KVSNWDS SEQ ID NO:418 sequence of NO:258 CDR 2 of AM_(L)24 Vl Amino acid SEQ ID MQGTHWPLCS SEQ ID NO:419 sequence of NO:259 CDR 3 of AM_(L)24 Vl Amino acid SEQ ID RASQAISIYLA SEQ ID NO:420 sequence of NO:260 CDR 1 of AM_(L)25 Vl Amino acid SEQ ID AASSLQS SEQ ID NO:421 sequence of NO:261 CDR 2 of AM_(L)25 Vl Amino acid SEQ ID QQYSSYPRT SEQ ID NO:422 sequence of NO:262 CDR 3 of AM_(L)25 Vl Amino acid SEQ ID RASQSVYSNLA SEQ ID NO:423 sequence of NO:263 CDR 1 of AM_(L)26 Vl Amino acid SEQ ID GASTRAT SEQ ID NO:424 sequence of NO:264 CDR 2 of AM_(L)26 Vl Amino acid SEQ ID QQYYNWPWT SEQ ID NO:425 sequence of NO:265 CDR 3 of AM_(L)26 Vl

As used herein, the term “antibody” refers to the various forms of monomeric or multimeric proteins comprising one or more polypeptide chains that specifically binds to an antigen, as variously described herein. In certain embodiments, antibodies are produced by recombinant DNA techniques. In additional embodiments, antibodies are produced by enzymatic or chemical cleavage of naturally occurring antibodies. In another aspect, the antibody is selected from the group consisting of: a) a human antibody; b) a humanized antibody; c) a chimeric antibody; d) a monoclonal antibody; e) a polyclonal antibody; f) a recombinant antibody; g) an antigen-binding antibody fragment; h) a single chain antibody; i) a diabody; j) a triabody; k) a tetrabody; 1) a Fab fragment; m) a F(ab′)₂ fragment; n) an IgD antibody; o) an IgE antibody; p) an IgM antibody; q) an IgA antibody; r) an IgG I antibody; s) an IgG2 antibody; t) an IgG3 antibody; and u) an IgG4 antibody.

Traditional antibody structural units typically comprise a tetramer. Each tetramer is typically composed of two identical pairs of polypeptide chains, each pair having one “light” (typically having a molecular weight of about 25 kDa) and one “heavy” chain (typically having a molecular weight of about 50-70 kDa). The amino-terminal portion of each chain includes a variable region of about 100 to 110 or more amino acids primarily responsible for antigen recognition. The carboxy-terminal portion of each chain defines a constant region primarily responsible for effector function. Human light chains are classified as kappa and lambda light chains. Heavy chains are classified as mu, delta, gamma, alpha, or epsilon, and define the antibody's isotype as IgM, IgD, IgG, IgA, and IgE, respectively. IgG has several subclasses, including, but not limited to IgG1, IgG2, IgG3, and IgG4. IgM has subclasses, including, but not limited to, IgM1 and IgM2. Embodiments of the invention include all such classes of antibodies that incorporate the variable domains or the CDRs of the antigen binding proteins, as described herein.

The general structure and properties of CDRs within naturally occurring antibodies have been described in the art. Briefly, in a traditional antibody scaffold, the CDRs are embedded within a framework in the heavy and light chain variable region where they constitute the regions largely responsible for antigen binding and recognition. A variable region comprises at least three heavy or light chain CDRs (Kabat et al., 1991, Sequences of Proteins of Immunological Interest, Public Health Service N.I.H., Bethesda, Md.; see also Chothia and Lesk, 1987, J. Mol. Biol. 196:901-917; Chothia et al., 1989, Nature 342: 877-883), within a framework region (designated framework regions 1-4, FR1, FR2, FR3, and FR4, by Kabat et al., 1991; see also Chothia and Lesk, 1987, supra). The CDRs provided by the present invention, however, may not only be used to define the antigen binding domain of a traditional antibody structure, but may be embedded in a variety of other scaffold structures, as described herein.

Antibodies of the invention can comprise any constant region known in the art. The light chain constant region can be, for example, a kappa- or lambda-type light chain constant region, e.g., a human kappa- or lambda-type light chain constant region. The heavy chain constant region can be, for example, an alpha-, delta-, epsilon-, gamma-, or mu-type heavy chain constant regions, e.g., a human alpha-, delta-, epsilon-, gamma-, or mu-type heavy chain constant region. In one embodiment, the light or heavy chain constant region is a fragment, derivative, variant, or mutein of a naturally occurring constant region.

The CDRs of the invention also include consensus sequences derived from groups of related monoclonal antibodies. The antibodies may be related by both sequence homology and function, as shown in the Examples. As described herein, a “consensus sequence” refers to amino acid sequences having conserved amino acids common among a number of sequences and variable amino acids that vary within given amino acid sequences. The CDR consensus sequences of the invention include CDRs corresponding to each of H-CDR1, H-CDR2, H-CDR3, L-CDR1, L-CDR2 and L-CDR3.

Consensus sequences were determined using standard phylogenic analyses of the CDRs corresponding to the VH (i.e., Variable Heavy, etc.) & VL of anti-IL-17RA antibodies. Two different approaches were employed. In a first approach, the consensus sequences were determined by keeping the CDRs contiguous within the same sequence corresponding to a VH or VL. In a second approach, the consensus sequences were determined by aligning the various types of CDRs, i.e., H-CDR1, H-CDR2, H-CDR3, L-CDR1, L-CDR2 and L-CDR3 sequences of the IL-17RA antigen binding proteins disclosed herein independently.

In the first approach, briefly, amino acid sequences corresponding to the entire variable domains of either VH or VL were converted to FASTA formatting for ease in processing comparative alignments and inferring phylogenies. Next, framework regions of these sequences were replaced with an artificial linker sequence (GGGAAAGGGAAA, SEQ ID NO:448) so that examination of the CDRs alone could be performed without introducing any amino acid position weighting bias due to coincident events (e.g., such as unrelated antibodies that serendipitously share a common germline framework heritage) whilst still keeping CDRs contiguous within the same sequence corresponding to a VH or VL. VH or VL sequences of this format were then subjected to sequence similarity alignment interrogation using a program that employs a standard ClutalW-like algorithm (see, Thompson et al., 1994, Nucleic Acids Res. 22:4673-4680). A gap creation penalty of 8.0 was employed along with a gap extension penalty of 2.0. This program likewise generated phylograms (phylogenic tree illustrations) based on sequence similarity alignments using either UPGMA (unweighted pair group method using arithmetic averages) or Neighbor-Joining methods (see, Saitou and Nei, 1987, Molecular Biology and Evolution 4:406-425) to construct & illustrate similarity and distinction of sequence groups via branch length comparison and grouping. Both methods produced similar results but UPGMA-derived trees were ultimately used as the method employs a simpler and more conservative set of assumptions. UPGMA-derived trees are shown in FIG. 1 where similar groups of sequences were defined as having fewer than 15 substitutions per 100 residues (see legend in tree illustrations for scale) amongst individual sequences within the group and were used to define consensus sequence collections. The original sequence alignments generated were employed to empirically examine and document the occurrence of amino acids tolerated at each position with a consensus group and are shown in FIGS. 2 and 3. Consensus sequences for the groups of similar sequences within each CDR were then prepared. Amino acids that varied within each group were noted with the notation X_(n) within each consensus sequence.

The H-CDR1 consensus sequences include amino acid sequences selected from the group consisting of: a) X₁YGIS (SEQ ID NO:453), wherein X₁ is selected from the group consisting of R, S and G; b) X₁YX₂MX₃ (SEQ ID NO:454), wherein X₁ is selected from the group consisting of D and S; X₂ is selected from the group consisting of Y and S; and X₃ is selected from the group consisting of S and N; and c) SYGMX₁ (SEQ ID NO:455), wherein X₁ is selected from the group consisting of H and Q;

The H-CDR2 consensus sequences include amino acid sequence selected from the group consisting of: a) WISX₁YX₂GNTX₃YAQX₄X₅QG (SEQ ID NO:456), wherein X₁ is selected from the group consisting of A and T; X₂ is selected from the group consisting of N, S and K; X₃ is selected from the group consisting of N and K; X₄ is selected from the group consisting of K and N; and X₅ is selected from the group consisting of L and F; b) X₁X₂SX₃X₄X₅SX₆IX₇YADSVKG (SEQ ID NO:457), wherein X₁ is selected from the group consisting of Y, I and F; X₂ is selected from the group consisting of I and S; X₃ is selected from the group consisting of S and A; X₄ is selected from the group consisting of S and R; and X₅ is selected from the group consisting of G, S and no amino acid; X₆ is selected from the group consisting of T and I; and X₇ is selected from the group consisting of Y and H; and c) VIWYDGX₁X₂KX₃YADSVKG (SEQ ID NO:458), wherein X₁ is selected from the group consisting of S and N; X₂ is selected from the group consisting of N and K; and X₃ is selected from the group consisting of H and Y.

The H-CDR3 consensus sequences include amino acid sequence selected from the group consisting of: a) X₁QLX₂X₃DY (SEQ ID NO:459), wherein X₁ is selected from the group consisting of R and K, X₂ is selected from the group consisting of Y, V, and A, and X₃ is selected from the group consisting of F and L and b) X₁QLX₂FDY (SEQ ID NO:460), wherein X₁ is selected from the group consisting of R and K, and X₂ is selected from the group consisting of Y and V.

The L-CDR1 consensus sequence includes an amino acid sequence selected from the group consisting of: a) RASQX₁IX₂X₃X₄LX₅ (SEQ ID NO:461), wherein X₁ is selected from the group consisting of G, S, and A; X₂ is selected from the group consisting of R and S; X₃ is selected from the group consisting of S, I and N; X₄ is selected from the group consisting of W and Y; and X₅ is selected from the group consisting of A and N; b) RASQSX₁X₂X₃X₄LA (SEQ ID NO:462), wherein X₁ is selected from the group consisting of V and I; X₂ is selected from the group consisting of I and S; X₃ is selected from the group consisting of S and T; X₄ is selected from the group consisting of N and S; and X₅ is selected from the group consisting of A and N; and c) RASQSVX₁X₂NLX₃ (SEQ ID NO:463), wherein X₁ is selected from the group consisting of Y and S; X₂ is selected from the group consisting of S and R; and X₃ is selected from the group consisting of A and V.

The L-CDR2 consensus sequence includes an amino acid sequence selected from the group consisting of: a) AASSX₁QS (SEQ ID NO:464), wherein X₁ is selected from the group consisting of L and F; b) AASX₁LQS (SEQ ID NO:465), wherein X₁ is selected from the group consisting of S and T; c) X₁X₂STRAX₃, wherein X₁ is selected from the group consisting of G and D; X₂ is selected from the group consisting of A and T; and X₃ is selected from the group consisting of T and A; and d) GASTRAX₁ (SEQ ID NO:466), wherein X₁ is selected from the group consisting of A, T and N.

The L-CDR3 consensus sequences include amino acid sequences selected from the group consisting of: a) LQHX₁SYX₂X₃T (SEQ ID NO:467), wherein X₁ is selected from the group consisting of K and N; X₂ is selected from the group consisting of P and N; and X₃ is selected from the group consisting of L, F and P; b) QX₁X₂X₃X₄X₅PX₆T (SEQ ID NO:468), wherein X₁ is selected from the group consisting of Q and K; X₂ is selected from the group consisting of A, S and Y; X₃ is selected from the group consisting of N, Y and S; X₄ is selected from the group consisting of N, S and R; X₅ is selected from the group consisting of F, T, Y and A; and X₆ is selected from the group consisting of R and F; c) QQYDX₁WPLT (SEQ ID NO:469), wherein X₁ is selected from the group consisting of N, T and I; and d) QX₁YX₂X₃WX₄X₅X₆T (SEQ ID NO:470), wherein X₁ is selected from the group consisting of H and Q; X₂ is selected from the group consisting of I, Y, N and K; X₃ is selected from the group consisting of N and S; X₄ is selected from the group consisting of P and R; X₅ is selected from the group consisting of K, no amino acid, and T; and X₆ is selected from the group consisting of W and no amino acid.

FIGS. 1, 2, 3, 8A, 8B, 11, and 14 show that a clear pattern in the data exists between sequence homology in the CDR domains and the antibodies function, as determined by cross-competition binning and the determination of where the antibodies bound to IL-17RA. Thus, a structure/function relation for classes of antibodies has been established for the IL-17RA antibodies provided herein.

In a second approach CDR consensus sequences were determined for each separate CDR, independently of their contiguous context within the same sequence corresponding to a VH or VL. In this approach the consensus sequences were determined by aligning each H-CDR1, H-CDR2, H-CDR3, L-CDR1, L-CDR2, and L-CDR3 in groups, i.e., by aligning the individual H-CDR1 sequences of the IL-17RA antigen binding proteins disclosed herein to determine a H-CDR1 consensus sequence, by aligning the individual H-CDR2 sequences of the IL-17RA antigen binding proteins disclosed herein to determine a H-CDR2 consensus sequence, by aligning the individual H-CDR3 sequences of the IL-17RA antigen binding proteins disclosed herein to determine a H-CDR3 consensus sequence, by aligning the individual L-CDR1 sequences of the IL-17RA antigen binding proteins disclosed herein to determine a L-CDR1 consensus sequence, by aligning the individual L-CDR2 sequences of the IL-17RA antigen binding proteins disclosed herein to determine a L-CDR2 consensus sequence, and by aligning the individual L-CDR3 sequences of the IL-17RA antigen binding proteins disclosed herein to determine a L-CDR3 consensus sequence. Similarities between sequences within each individual CDR sequences were identified. Consensus sequences for the groups of similar sequences within each CDR were then prepared. Amino acids that varied within each group were noted with the notation X_(n) within each consensus sequence.

Within light and heavy chains, the variable and constant regions are joined by a “J” region of about twelve (12) or more amino acids, with the heavy chain also including a “D” region of about ten (10) more amino acids. See, generally, Paul, W., ed., 1989, Fundamental Immunology Ch. 7, 2nd ed. Raven Press, N.Y. The variable regions of each light/heavy chain pair form the antibody binding site. Scaffolds of the invention include such regions.

Some naturally occurring antibodies, for example found in camels and llamas, are dimers consisting of two heavy chain and include no light chains. Muldermans et al., 2001, J. Biotechnol. 74:277-302; Desmyter et al., 2001, J. Biol. Chem. 276:26285-26290. Crystallographic studies of a camel antibody have revealed that the CDR3 regions form a surface that interacts with the antigen and thus is critical for antigen binding like in the more typical tetrameric antibodies. The invention encompasses dimeric antibodies consisting of two heavy chains, or fragments thereof, that can bind to and/or inhibit the biological activity of IL-17RA.

The variable regions of the heavy and light chains typically exhibit the same general structure of relatively conserved framework regions (FR) joined by three hypervariable regions, i.e., the complementarity determining regions or CDRs. The CDRs are the hypervariable regions of an antibody (or antigen binding protein, as outlined herein), that are responsible for antigen recognition and binding. The CDRs from the two chains of each pair are aligned by the framework regions, enabling binding to a specific epitope. From N-terminal to C-terminal, both light and heavy chains comprise the domains FR1, CDR1, FR2, CDR2, FR3, CDR3 and FR4. The assignment of amino acids to each domain is in accordance with the definitions of Kabat Sequences of Proteins of Immunological Interest. Chothia et al., 1987, J. Mol. Biol. 196:901-917; Chothia et al., 1989, Nature 342:878-883. Scaffolds of the invention include such regions.

CDRs constitute the major surface contact points for antigen binding. See, e.g., Chothia and Lesk, 1987, J. Mol. Biol. 196:901-917. Further, CDR3 of the light chain and, especially, CDR3 of the heavy chain may constitute the most important determinants in antigen binding within the light and heavy chain variable regions. See, e.g., Chothia and Lesk, 1987, supra; Desiderio et al., 2001, J. Mol. Biol. 310:603-615; Xu and Davis, 2000, Immunity 13:37-45; Desmyter et al., 2001, J. Biol. Chem. 276:26285-26290; and Muyldermans, 2001, J. Biotechnol. 74:277-302. In some antibodies, the heavy chain CDR3 appears to constitute the major area of contact between the antigen and the antibody. Desmyter et al., 2001, supra. In vitro selection schemes in which CDR3 alone is varied can be used to vary the binding properties of an antibody. Muyldermans, 2001, supra; Desiderio et al. 2001, supra.

Naturally occurring antibodies typically include a signal sequence, which directs the antibody into the cellular pathway for protein secretion and which is not present in the mature antibody. A polynucleotide encoding an antibody of the invention may encode a naturally occurring signal sequence or a heterologous signal sequence as described below.

In some embodiments, however, the scaffold components can be a mixture from different species. As such, if the antigen binding protein is an antibody, such antibody may be a chimeric antibody and/or a humanized antibody. In general, both “chimeric antibodies” and “humanized antibodies” refer to antibodies that combine regions from more than one species. For example, “chimeric antibodies” traditionally comprise variable region(s) from a mouse (or rat, in some cases) and the constant region(s) from a human.

“Humanized antibodies” generally refer to non-human antibodies that have had the variable-domain framework regions swapped for sequences found in human antibodies. Generally, in a humanized antibody, the entire antibody, except the CDRs, is encoded by a polynucleotide of human origin or is identical to such an antibody except within its CDRs. The CDRs, some or all of which are encoded by nucleic acids originating in a non-human organism, are grafted into the beta-sheet framework of a human antibody variable region to create an antibody, the specificity of which is determined by the engrafted CDRs. The creation of such antibodies is described in, e.g., WO 92/11018, Jones, 1986, Nature 321:522-525, Verhoeyen et al., 1988, Science 239:1534-1536. Humanized antibodies can also be generated using mice with a genetically engineered immune system. Roque et al., 2004, Biotechnol. Prog. 20:639-654. In the present invention, the identified CDRs are human, and thus both humanized and chimeric antibodies in this context include some non-human CDRs; for example, humanized antibodies may be generated that comprise the CDRH3 and CDRL3 regions, with one or more of the other CDR regions being of a different special origin.

In one embodiment, the antibodies of the invention are a multispecific antibody, and notably a bispecific antibody, also sometimes referred to as “diabodies”. These are antibodies that bind to two (or more) different antigens. Diabodies can be manufactured in a variety of ways known in the art (Holliger and Winter, 1993, Current Opinion Biotechnol. 4:446-449), e.g., prepared chemically or from hybrid hybridomas.

In one embodiment, the antibody of the invention is a minibody. Minibodies are minimized antibody-like proteins comprising a scFv joined to a CH3 domain. Hu et al., 1996, Cancer Res. 56:3055-3061. In one embodiment, the antibody of the invention is a domain antibody; see, for example U.S. Pat. No. 6,248,516. Domain antibodies (dAbs) are functional binding domains of antibodies, corresponding to the variable regions of either the heavy (VH) or light (VL) chains of human antibodies dABs have a molecular weight of approximately 13 kDa, or less than one-tenth the size of a full antibody. dABs are well expressed in a variety of hosts including bacterial, yeast, and mammalian cell systems. In addition, dAbs are highly stable and retain activity even after being subjected to harsh conditions, such as freeze-drying or heat denaturation. See, for example, U.S. Pat. Nos. 6,291,158; 6,582,915; 6,593,081; 6,172,197; US Serial No. 2004/0110941; European Patent 0368684; U.S. Pat. No. 6,696,245, WO04/058821, WO04/003019 and WO03/002609.

In one embodiment, the antibody of the invention is an antibody fragment that retains binding specificity to IL-17RA. In various embodiments, the antibody fragments comprise, but are not limited to, a F(ab), F(ab′), F(ab′)2, Fv, or a single chain Fv fragments. At a minimum, an antibody, as meant herein, comprises a polypeptide that can bind specifically to IL-17RA comprising all or part of a light or heavy chain variable region, such as one or more CDRs.

Further examples of IL-17RA-binding antibody fragments (to be clear, IL-17RA-binding antibody fragments that either compete for binding to human IL-17RA with at least one of the IL-17RA neutralizing antibodies described herein, or bind to one or more of the neutralizing determinants on IL-17RA described herein) include, but are not limited to, (i) the Fab fragment consisting of VL, VH, CL and CH1 domains, (ii) the Fd fragment consisting of the VH and CH1 domains, (iii) the Fv fragment consisting of the VL and VH domains of a single antibody; (iv) the dAb fragment (Ward et al., 1989, Nature 341:544-546) which consists of a single variable, (v) isolated CDR regions, (vi) F(ab′)₂ fragments, a bivalent fragment comprising two linked Fab fragments (vii) single chain Fv molecules (scFv), wherein a VH domain and a VL domain are linked by a peptide linker which allows the two domains to associate to form an antigen binding site (Bird et al., 1988, Science 242:423-426, Huston et al., 1988, Proc. Natl. Acad. Sci. U.S.A. 85:5879-5883), (viii) bispecific single chain Fv dimers (PCT/US92/09965) and (ix) “diabodies” or “triabodies”, multivalent or multispecific fragments constructed by gene fusion (Tomlinson et. al., 2000, Methods Enzymol. 326:461-479; WO94/13804; Holliger et al., 1993, Proc. Natl. Acad. Sci. U.S.A. 90:6444-6448). The antibody fragments may be modified. For example, the molecules may be stabilized by the incorporation of disulphide bridges linking the VH and VL domains (Reiter et al., 1996, Nature Biotech. 14:1239-1245). Aspects of the invention include embodiments wherein the non-CDR components of these fragments are human sequences.

In one embodiment, the antibody of the invention is a fully human antibody. In this embodiment, as outlined above, specific structures comprise complete heavy and light chains depicted comprising the CDR regions. Additional embodiments utilize one or more of the CDRs of the invention, with the other CDRs, framework regions, J and D regions, constant regions, etc., coming from other human antibodies. For example, the CDRs of the invention can replace the CDRs of any number of human antibodies, particularly commercially relevant antibodies

Single chain antibodies may be formed by linking heavy and light chain variable domain (Fv region) fragments via an amino acid bridge (short peptide linker), resulting in a single polypeptide chain. Such single-chain Fvs (scFvs) have been prepared by fusing DNA encoding a peptide linker between DNAs encoding the two variable domain polypeptides (V_(L) and V_(H)). The resulting polypeptides can fold back on themselves to form antigen-binding monomers, or they can form multimers (e.g., dimers, trimers, or tetramers), depending on the length of a flexible linker between the two variable domains (Kortt et al., 1997, Prot. Eng. 10:423; Kortt et al., 2001, Biomol. Eng. 18:95-108). By combining different V_(L) and V_(H)-comprising polypeptides, one can form multimeric scFvs that bind to different epitopes (Kriangkum et al., 2001, Biomol. Eng. 18:31-40). Techniques developed for the production of single chain antibodies include those described in U.S. Pat. No. 4,946,778; Bird, 1988, Science 242:423; Huston et al., 1988, Proc. Natl. Acad. Sci. USA 85:5879; Ward et al., 1989, Nature 334:544, de Graaf et al., 2002, Methods Mol Biol. 178:379-87.

In one embodiment, the antibodies that compete for binding to human IL-17RA with the IL-17RA neutralizing antibodies described herein, or antibodies that bind to the neutralizing determinants described herein may be an antibody fusion protein (sometimes referred to herein as an “antibody conjugate”). The conjugate partner can be proteinaceous or non-proteinaceous; the latter generally being generated using functional groups on the antigen binding protein (see the discussion on covalent modifications of the antigen binding proteins) and on the conjugate partner. For example linkers are known in the art; for example, homo- or hetero-bifunctional linkers as are well known (see, 1994 Pierce Chemical Company catalog, technical section on cross-linkers, pages 155-200, incorporated herein by reference).

In one embodiment, the antibodies that compete for binding to human IL-17RA with the IL-17RA neutralizing antibodies described herein, or antibodies that bind to the neutralizing determinants described herein may be an antibody analog, sometimes referred to as “synthetic antibodies.” For example, a variety of recent work utilizes either alternative protein scaffolds or artificial scaffolds with grafted CDRs. Such scaffolds include, but are not limited to, mutations introduced to stabilize the three-dimensional structure of the binding protein as well as wholly synthetic scaffolds consisting for example of biocompatible polymers. See, for example, Korndorfer et al., 2003, Proteins: Structure, Function, and Bioinformatics, Volume 53, Issue 1:121-129. Roque et al., 2004, Biotechnol. Prog. 20:639-654. In addition, peptide antibody mimetics (“PAMs”) can be used, as well as work based on antibody mimetics utilizing fibronection components as a scaffold. As it is known in the art, a number of different programs can be used to identify the degree of sequence identity or similarity a protein or nucleic acid has to a known sequence.

By “protein,” as used herein, is meant at least two covalently attached amino acids, which includes proteins, polypeptides, oligopeptides and peptides. In some embodiments, the two or more covalently attached amino acids are attached by a peptide bond. The protein may be made up of naturally occurring amino acids and peptide bonds, for example when the protein is made recombinantly using expression systems and host cells, as outlined below. Alternatively, the protein may include synthetic amino acids (e.g., homophenylalanine, citrulline, ornithine, and norleucine), or peptidomimetic structures, i.e., “peptide or protein analogs”, such as peptoids (see, Simon et al., 1992, Proc. Natl. Acad. Sci. U.S.A. 89:9367, incorporated by reference herein), which can be resistant to proteases or other physiological and/or storage conditions. Such synthetic amino acids may be incorporated in particular when the antigen binding protein is synthesized in vitro by conventional methods well known in the art. In addition, any combination of peptidomimetic, synthetic and naturally occurring residues/structures can be used. “Amino acid” also includes imino acid residues such as proline and hydroxyproline. The amino acid “R group” or “side chain” may be in either the (L)- or the (S)-configuration. In a specific embodiment, the amino acids are in the (L)- or (S)-configuration.

In some embodiments, the antigen binding proteins of the invention are isolated proteins or substantially pure proteins. An “isolated” protein is unaccompanied by at least some of the material with which it is normally associated in its natural state, for example constituting at least about 5%, or at least about 50% by weight of the total protein in a given sample. It is understood that the isolated protein may constitute from 5 to 99.9% by weight of the total protein content depending on the circumstances. For example, the protein may be made at a significantly higher concentration through the use of an inducible promoter or high expression promoter, such that the protein is made at increased concentration levels. The definition includes the production of an antigen binding protein in a wide variety of organisms and/or host cells that are known in the art.

For amino acid sequences, sequence identity and/or similarity is determined by using standard techniques known in the art, including, but not limited to, the local sequence identity algorithm of Smith and Waterman, 1981, Adv. Appl. Math. 2:482, the sequence identity alignment algorithm of Needleman and Wunsch, 1970, J. Mol. Biol. 48:443, the search for similarity method of Pearson and Lipman, 1988, Proc. Nat. Acad. Sci. U.S.A. 85:2444, computerized implementations of these algorithms (GAP, BESTFIT, FASTA, and TFASTA in the Wisconsin Genetics Software Package, Genetics Computer Group, 575 Science Drive, Madison, Wis.), the Best Fit sequence program described by Devereux et al., 1984, Nucl. Acid Res. 12:387-395, preferably using the default settings, or by inspection. Preferably, percent identity is calculated by FastDB based upon the following parameters: mismatch penalty of 1; gap penalty of 1; gap size penalty of 0.33; and joining penalty of 30, “Current Methods in Sequence Comparison and Analysis,” Macromolecule Sequencing and Synthesis, Selected Methods and Applications, pp 127-149 (1988), Alan R. Liss, Inc. An example of a useful algorithm is PILEUP. PILEUP creates a multiple sequence alignment from a group of related sequences using progressive, pairwise alignments. It can also plot a tree showing the clustering relationships used to create the alignment. PILEUP uses a simplification of the progressive alignment method of Feng & Doolittle, 1987, J. Mol. Evol. 35:351-360; the method is similar to that described by Higgins and Sharp, 1989, CABIOS 5:151-153. Useful PILEUP parameters including a default gap weight of 3.00, a default gap length weight of 0.10, and weighted end gaps.

Another example of a useful algorithm is the BLAST algorithm, described in: Altschul et al., 1990, J. Mol. Biol. 215:403-410; Altschul et al., 1997, Nucleic Acids Res. 25:3389-3402; and Karin et al., 1993, Proc. Natl. Acad. Sci. U.S.A. 90:5873-5787. A particularly useful BLAST program is the WU-BLAST-2 program which was obtained from Altschul et al., 1996, Methods in Enzymology 266:460-480. WU-BLAST-2 uses several search parameters, most of which are set to the default values. The adjustable parameters are set with the following values: overlap span=1, overlap fraction=0.125, word threshold (T)=II. The HSP S and HSP S2 parameters are dynamic values and are established by the program itself depending upon the composition of the particular sequence and composition of the particular database against which the sequence of interest is being searched; however, the values may be adjusted to increase sensitivity.

An additional useful algorithm is gapped BLAST as reported by Altschul et al., 1993, Nucl. Acids Res. 25:3389-3402. Gapped BLAST uses BLOSUM-62 substitution scores; threshold T parameter set to 9; the two-hit method to trigger ungapped extensions, charges gap lengths of k a cost of 10+k; X_(u) set to 16, and X_(g) set to 40 for database search stage and to 67 for the output stage of the algorithms. Gapped alignments are triggered by a score corresponding to about 22 bits.

Amino acid substitutions are typically of single residues; insertions usually will be on the order of from about one (1) to about twenty (20) amino acid residues, although considerably larger insertions may be tolerated. Deletions range from about one (1) to about twenty (20) amino acid residues, although in some cases deletions may be much larger.

Substitutions, deletions, insertions or any combination thereof may be used to arrive at a final derivative or variant. Generally these changes are done on a few amino acids to minimize the alteration of the molecule, particularly the immunogenicity and specificity of the antigen binding protein. However, larger changes may be tolerated in certain circumstances. Conservative substitutions are generally made in accordance with the following chart depicted as TABLE 2.

TABLE 2 Original Residue Exemplary Substitutions Ala Ser Arg Lys Asn Gln, His Asp Glu Cys Ser Gln Asn Glu Asp Gly Pro His Asn, Gln Ile Leu, Val Leu Ile, Val Lys Arg, Gln, Glu Met Leu, Ile Phe Met, Leu, Tyr Ser Thr Thr Ser Trp Tyr Tyr Trp, Phe Val Ile, Leu

Substantial changes in function or immunological identity are made by selecting substitutions that are less conservative than those shown in TABLE 2. For example, substitutions may be made which more significantly affect: the structure of the polypeptide backbone in the area of the alteration, for example the alpha-helical or beta-sheet structure; the charge or hydrophobicity of the molecule at the target site; or the bulk of the side chain. The substitutions which in general are expected to produce the greatest changes in the polypeptide's properties are those in which (a) a hydrophilic residue, e.g., seryl or threonyl, is substituted for (or by) a hydrophobic residue, e.g., leucyl, isoleucyl, phenylalanyl, valyl or alanyl; (b) a cysteine or proline is substituted for (or by) any other residue; (c) a residue having an electropositive side chain, e.g., lysyl, arginyl, or histidyl, is substituted for (or by) an electronegative residue, e.g., glutamyl or aspartyl; or (d) a residue having a bulky side chain, e.g., phenylalanine, is substituted for (or by) one not having a side chain, e.g., glycine.

The variants typically exhibit the same qualitative biological activity and will elicit the same immune response as the naturally-occurring analogue, although variants also are selected to modify the characteristics of the antigen binding protein proteins as needed. Alternatively, the variant may be designed such that the biological activity of the antigen binding protein is altered. For example, glycosylation sites may be altered or removed as discussed herein.

Antibodies that compete for binding to human IL-17RA with the IL-17RA neutralizing antibodies described herein, or antibodies that bind to the neutralizing determinants described herein may comprise oligomers that contain one or more antibody polypeptides. Oligomers may be in the form of covalently-linked or non-covalently-linked dimers, trimers, or higher oligomers. Oligomers comprising two or more IL-17RA antibody polypeptides are contemplated for use, with one example being a homodimer. Other oligomers include heterodimers, homotrimers, heterotrimers, homotetramers, heterotetramers, etc. Such oligomers may be joined via covalent or non-covalent interactions between peptide moieties fused to the IL-17RA antibody polypeptides. Such peptides may be peptide linkers (spacers), or peptides that have the property of promoting oligomerization. Leucine zippers and certain polypeptides derived from antibodies are among the peptides that can promote oligomerization of IL-17RA antibody polypeptides attached thereto, as described in more detail below.

In one embodiment, an oligomer is prepared using polypeptides derived from immunoglobulins. Preparation of fusion proteins comprising certain heterologous polypeptides fused to various portions of antibody-derived polypeptides (including the Fc domain) has been described, e.g., by Ashkenazi et al., 1991, PNAS USA 88:10535; Byrn et al., 1990, Nature 344:677; and Hollenbaugh et al., 1992 “Construction of Immunoglobulin Fusion Proteins”, in Current Protocols in Immunology, Suppl. 4, pages 10.19.1-10.19.11.

One embodiment is directed to a dimer comprising two fusion proteins created by fusing an IL-17RA binding fragment of an IL-17RA antibody to the Fc region of an antibody. The dimer can be made by, for example, inserting a gene fusion encoding the fusion protein into an appropriate expression vector, expressing the gene fusion in host cells transformed with the recombinant expression vector, and allowing the expressed fusion protein to assemble much like antibody molecules, whereupon interchain disulfide bonds form between the Fc moieties to yield the dimer.

The term “Fc polypeptide” as used herein includes native and mutein forms of polypeptides derived from the Fc region of an antibody. Truncated forms of such polypeptides containing the hinge region that promotes dimerization also are included. Fusion proteins comprising Fc moieties (and oligomers formed therefrom) offer the advantage of facile purification by affinity chromatography over Protein A or Protein G columns.

One suitable Fc polypeptide, described in PCT application WO 93/10151 (hereby incorporated by reference), is a single chain polypeptide extending from the N-terminal hinge region to the native C-terminus of the Fc region of a human IgG antibody. Another useful Fc polypeptide is the Fc mutein described in U.S. Pat. No. 5,457,035 and in Baum et al., 1994, EMBO J. 13:3992-4001. The amino acid sequence of this mutein is identical to that of the native Fc sequence presented in WO 93/10151, except that amino acid 19 has been changed from Leu to Ala, amino acid 20 has been changed from Leu to Glu, and amino acid 22 has been changed from Gly to Ala. The mutein exhibits reduced affinity for Fc receptors.

Use of Antibodies that Compete for Binding with the IL-17RA Antibodies, or Antibodies that Bind IL-17RA Neutralizing Determinants for Diagnostic and Therapeutic Purposes

Antibodies that compete for binding to human IL-17RA with the IL-17RA neutralizing antibodies described herein, or antibodies that bind to the neutralizing determinants described herein can be used in diagnostic assays, e.g., binding assays to detect and/or quantify IL-17RA expressed in a tissue or cell. Said antibodies may be used in research to further investigate the role of IL-17RA in disease. Said antibodies may be used to further investigate the role of IL-17RA in forming homomeric and/or heteromeric receptor complexes and the role of said complexes in disease. Said antibodies may be used to further investigate the role of IL-17RA activation to homomeric and/or heteromeric IL-17 ligand complexes. Said antibodies may be used to further investigate the role of IL-17RA activation to homomeric and/or heteromeric IL-17 ligand complexes and how said homomeric and/or heteromeric IL-17 ligand complexes relate to disease.

The IL-17RA neutralizing antibodies and antibodies that compete for binding to human IL-17RA with the IL-17RA neutralizing antibodies described herein, or antibodies that bind to the neutralizing determinants described herein can be used for the prevention or treatment of diseases or conditions associated with the IL-17A and/or IL-17F activity. A disease or condition associated with IL-17A and/or IL-17F means any disease, condition, or pathology whose onset in a patient is caused or exacerbated by the interaction of IL-17A and/or IL-17F with IL-17RA. The severity of the disease, condition, or pathology can also be increased or decreased by the modulating the interaction of IL-17A and/or IL-17F with IL-17RA or a heterologous complex comprising IL-17RA and IL-17RC.

Antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein or antibodies that bind to the neutralizing determinants described herein may be used to reduce IL-17RA activity. Antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein or antibodies that bind to the neutralizing determinants described herein may be used to inhibit binding and/or signaling of IL-17A and/or IL-17F to IL-17RA. In certain embodiments, the antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein or antibodies that bind to the neutralizing determinants described herein inhibits binding and/or signaling of IL-17A and IL-17F to IL-17RA. In additional embodiments, the antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein or antibodies that bind to the neutralizing determinants described herein inhibits binding and/or signaling of IL-17A but not IL-17F to IL-17RA. In other embodiments, the antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein or antibodies that bind to the neutralizing determinants described herein inhibits binding and/or signaling of IL-17F and not IL-17A to IL-17RA. The antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein or antibodies that bind to the neutralizing determinants described herein may be used in treating the consequences, symptoms, and/or the pathology associated with IL-17RA activity. The antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein or antibodies that bind to the neutralizing determinants described herein may be used to inhibit the production of one or more of an inflammatory cytokine, chemokine, matrix metalloproteinase, or other molecule associated with IL-17RA activation. The antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein or antibodies that bind to the neutralizing determinants described herein may be used in methods of inhibiting production of molecules such as but is not limited to: IL-6, IL-8, CXCL1, CXCL2, GM-CSF, G-CSF, M-CSF, IL-1□, TNF□, RANK-L, LIF, PGE2, IL-12, MMPs (such as but not limited to MMP3 and MMP9), GRO□, NO, and/or C-telopeptide and the like, comprising administering an antigen binding protein. The antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein or antibodies that bind to the neutralizing determinants described herein inhibit proinflammatory and proautoimmune immune responses and may be used to treat diseases associated with activity of the IL-17A and/or IL-17F/IL-17RA pathway.

Aspects of the invention include antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein or antibodies that bind to the neutralizing determinants described herein that specifically bind to human IL-17RA and partially or fully inhibit IL-17RA from forming either a homomeric or heteromeric functional receptor complex, such as, but not limited to IL-17RA/IL-17RC complex and do not necessarily inhibit IL-17A and/or IL-17F or an IL-17A/IL-17F heteromer from binding to IL-17RA or a IL-17RA heteromeric receptor complex. Thus, disease states associated with IL-17RC are also associated with IL-17RA due to the fact that IL-17RC cannot signal without IL-17RA. For example, see You, Z., et al., Cancer Res., 2006 Jan. 1; 66(1):175-83 and You, Z., et al., Neoplasia, 2007 June; 9(6):464-70.

Antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein or antibodies that bind to the neutralizing determinants described herein can be used for diagnostic purposes to detect, diagnose, or monitor diseases and/or conditions associated with IL-17A or IL-17RA. The invention provides for the detection of the presence of IL-17RA in a sample using classical immunohistological methods known to those of skill in the art (e.g., Tijssen, 1993, Practice and Theory of Enzyme Immunoassays, vol 15 (Eds R. H. Burdon and P. H. van Knippenberg, Elsevier, Amsterdam); Zola, 1987, Monoclonal Antibodies: A Manual of Techniques, pp. 147-158 (CRC Press, Inc.); Jalkanen et al., 1985, J. Cell. Biol. 101:976-985; Jalkanen et al., 1987, J. Cell Biol. 105:3087-3096). The detection of IL-17RA can be performed in vivo or in vitro.

Diagnostic applications provided herein include use of the antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein or antibodies that bind to the neutralizing determinants described herein to detect expression of IL-17RA and binding of the ligands to IL-17RA. Examples of methods useful in the detection of the presence of IL-17RA include immunoassays, such as the enzyme linked immunosorbent assay (ELISA) and the radioimmunoassay (RIA).

One aspect of the invention provides for identifying a cell or cells that express IL-17RA. In a specific embodiment, the antibodies that compete for binding with the IL-17RA neutralizing antibodies described herein or antibodies that bind to the neutralizing determinants described herein is labeled with a labeling group and the binding of the labeled antigen binding protein to IL-17RA is detected.

All references cited within the body of the instant specification are hereby expressly incorporated by reference in their entirety.

EXAMPLES

The following examples, including the experiments conducted and the results achieved, are provided for illustrative purposes only and are not to be construed as limiting the invention.

Example 1

IL-17RA neutralizing antibodies were shown to reduce incidence of arthritis in a CIA (Collagen-Induced Arthritis) mouse model when administered prophylactically and therapeutically. The IL-17RA inhibition reduced clinical arthritis in both a prophylactic and therapeutic manner for several models if CIA.

The surrogate neutralizing mouse IL-17RA mAb administered prophylactically reduced mean clinical scores in wild-type CIA model in a dose-dependent manner. FIG. 4 shows the dose-dependent inhibition by IL-17RA mAb in wild-type CIA model. Mice were treated with either IL-17RA mAb or control Ig on a Monday, Wednesday and Friday schedule for 2.5 weeks post boost. Administration of 100 μg and 300 μg of IL-17RA antibodies resulted in a lower clinical score for 18 days post-boost than compared to isotype control Ig.

A reduction in bone loss and cartilage erosion in the joint was associated with the reduction of mean clinical scores at the 300 μg dose of the IL-17RA mAb. Histopathologic analysis and radiographic images analysis were compared to the IgG control. By both means of analysis, the ankle joint of the near paw of CBA/1 male mouse treated with an IL-18R mAb (isotype control) showed marked inflammation: subchondrial bone erosion of the talus, marked joint architecture disruption of tarsal-metatarsal joints (subchondrial bone and articular cartilage erosion), and reactive periosteal bone formation (osteophytosis). In stark contrast, the ankle joint of the rear paw of a DBA/1 mouse treated with 300 μg anti-IL-17RA mAb showed well-defined joint spaces, lack of edema and lack of periosteal reactive bone or lytic lesions indicated reduced bone loss and cartilage erosion.

Example 2

IL-17RA inhibition was also shown to be effective in a CIA model when dosing was initiated after the onset of clinical signs (i.e, therapeutic dosing protocol) in a wild-type and TNFR p55/p75 KO model. Treatment was initiated approximately 6-7 days post collagen introduction in both models. FIG. 5 shows that therapeutic treatment with IL-17RA mAb stabilized mean clinical scores in both wild-type mice. FIG. 6 shows that therapeutic treatment with IL-17RA mAb stabilized mean clinical scores in TNFR p55/p75 KO models. Mice were treated with either an IL-17RA mAb, IL-1R mAb, or control Ig on a Monday, Wednesday and Friday schedule for 2 weeks post randomization into therapeutic treatment groups. These data are representative of 2 independent experiments performed in both WT and TNFR p55/p75 KO CIA models. Administering IL-17RA mAbs showed a reduced clinical score as compared to control IgG in CIA induced wild-type mice. Surprisingly, the similar efficacy of IL-17RA InAbs in the TNF p55/p75 KO model stabilized CIA independently of TNF signaling. This data suggests IL-17RA neutralizing antibodies therapy may pick up non-responsers to anti-TNF therapies. Combination therapy of an IL-17RA antigen binding protein with anti-TNF therapies may be more beneficial than either alone.

Example 3

The development of fully human monoclonal antibodies directed against human IL-17RA was carried out using Abgenix (now Amgen Fremont Inc.) XenoMouse® technology (U.S. Pat. Nos. 6,114,598; 6,162,963; 6,833,268; 7,049,426; 7,064,244, which are incorporated herein by reference in their entirety; Green et al, 1994, Nature Genetics 7:13-21; Mendez et al., 1997, Nature Genetics 15:146-156; Green and Jakobovitis, 1998, J. Ex. Med. 188:483-495)). TABLE 4 shows the portions of the IL-17RA protein used as an immunogen and cell lines used to generate and screen anti-IL-17RA antibodies.

TABLE 4 Reagent Description IL-17RA.Fc Human IL-17RA extracellular domain with a C-terminal human Fc domain. Expressed in a stable CHO cell line. IL-17RA-FLAG-polyHis Human IL-17RA extracellular domain (SEQ ID NO: 431) with a C-terminal FLAG-polyHis tag. Expressed by transient transfection in COS PKB cells. IL-17RA CHO cells Human IL-17RA full-length expressed on the surface of CHO cells.

IgG2 XenoMouse® mice were immunized/boosted with IL-17RA-Fc (group 1) and IL-17RA-FLAG-polyHis (group 2). Serum titers were monitored by ELISA and mice with the best titers were fused to generate hybridomas. The resulting polyclonal supernatants were screened for binding to IL-17RA by ELISA, and the positive supernatants were screened for binding to IL-17RA CHO cells by FMAT. Positive supernatants were subjected to additional screening. IgG2 XenoMouse® mice were immunized with the following immunogens: IL-17RA-Fc (group 3) and IL-17RA-FLAG-pHis (group 4) and were tested following additional immunizations.

Example 4

The IL-17RA antibodies were characterized. Non-clonal hybridoma supernatants were prepared in volumes of 1-2 mls (the Ig concentrations were not determined for these supernatants). The anti-IL-17RA non-clonal hybridoma supernatants were initially screened by FACS for their ability to inhibit biotinylated human IL-17A binding to CHO cells over-expressing human IL-17RA and another CHO cell line over-expressing cynomolgus IL-17RA. Nonclonal supernatants that were able to completely or nearly completely inhibit binding of human IL-17A to CHO-huIL-17RA and CHO-cynoIL-17RA were subsequently screened at several dilutions in an IL-17A-induced cytokine/chemokine secretion assay using a human foreskin fibroblast (HFF) cell line. Anti-IL-17RA non-clonal supernatants were incubated with HFF cells (5000 cells/well in 96 well plate) for 30 minutes at 36° C. and then stimulated overnight with either IL-17A (5 ng/ml) alone or IL-17F (20 ng/ml) and TNF-alpha (5 ng/ml). Fibroblast culture supernatants were then analyzed by ELISA for the presence of either IL-6 or GRO-alpha. Anti-IL-17RA non-clonal hybridomas were selected for sub-cloning based on their performance in the CHO-IL-17RA FACS assay and HFF bioassay. An example of the selection is shown in TABLES 5, 6, and 7.

TABLE 5 HFF Bioassay Repeat assays 1:4 dil. 1:32 1:4 1:32 1:128 % inhibition of IL-6 % positive % positive MFI production Neg. Cntl. 1.09 1.57 10 IL-17 biot. (500 ng/ml) 8.85 10.22 77 Supernatant I.D.  1 1.34 1.78 9 56 14 2 (incl. AM_(H)15/AM_(L)15) 0.60 3.77 6 80 72 98 91 81  3 1.04 1.60 8 46 −5 4 (incl. AM_(H)14/AM_(L)14) 1.72 0.79 10 90 82 99 92 84  5 1.59 1.43 11 76 52  6 1.45 1.93 14 82 79  7 1.00 1.28 8 71 58  8 1.43 1.60 14 69 31  9 1.34 2.28 18 59 20 10 0.79 1.96 11 58 −2 11 1.93 1.69 11 72 21 12 2.23 1.69 8 69 7 13 (incl. 1.49 0.49 6 82 53 AM_(H)21/AM_(L)21) 14 1.01 1.25 8 63 23 15 1.31 1.45 9 74 45 16 1.39 0.72 8 58 4 17 0.91 0.94 7 73 38 18 1.37 2.85 13 49 6 19 1.47 1.15 8 74 61 20 1.60 1.20 7 72 46 21 1.30 1.65 8 47 4 22 0.93 1.02 8 54 16 23 1.08 1.12 7 72 59

In TABLE 5, anti-IL-17RA non-clonal hybridoma supernatants were screened for binding to IL-17RA. The first half of TABLE 5 shows the % positive and mean fluorescent intensity (MFI) in results from flow cytometry (i.e, FACS). The % positive shows inhibition of biotin-huIL-17A binding to huIL-17RA⁺ CHO cells by the non-clonal hybridoma supernatants. The MFI column shows inhibition of biotinylated huIL-17A binding to cyno IL-17RA⁺ CHO cells by the non-clonal hybridoma supernatants. The second half of TABLE 5 shows the HFF binding intensity for the non-clonal and mAbs as measured by the % intensity of IL-6 production. The first 2 columns show an IL-17A/HFF bioassay with non-clonal hybridoma supernatants and the last 4 columns are repeat IL-17A/HFF bioassay results with non-clonal hybridoma supernatants.

TABLE 6 FACS results on 293-Cyno IL-17RA- expressing Cells HFF bioassay repeat 1:4 dilution 1:32 1:4 1:32 1:128 1:512 % positive % positive MFI % inhibition of IL-6 production Neg. Cntl 1.09 1.57 1.0 IL-17 biot. (500 ng/ml) 8.85 10.22 77 Supernatant I.D. 1 (incl. 1.32 1.4 9 AM_(H)11/AM_(L)11)  2 0.87 2.92 9  3 1.0 4.47 16  4 1.03 5.01 17  5 0.6 6.53 18  6 (incl. 0.73 4.55 9 AM_(H)5/AM_(L)5)  7 0.59 5.18 8  8 0.45 7.25 7  9 2.34 2.36 6 61 36 10 6.76 8.35 64 37 12 11 0.78 1.16 6 61 24 12 0.61 1.64 6 74 56 71 67 45 35 13 2.98 5.48 22 −2 −13 14 5.34 10.64 49 22 2 3 39 31 34 15 0.5 3.24 11 51 −7 16 (incl. 0.54 2.93 18 92 72 91 73 73 29 AM_(H)22/AM_(L)22) 17 1.25 2.2 17 −8 −76 18 0.61 0.99 7 73 28 19 (incl. AM_(H)23) 0.69 1.72 10 79 72 86 76 67 50 20 1.53 1.94 31 5 −31 21 6.66 9.63 66 −15 4 22 6.33 10.32 71 1 14 23 0.3 2.55 7 50 35 24 0.24 4.11 6 34 15 25 0.81 0.99 8 −49 11 26 0.43 1.31 7 67 48 27 0.7 1.23 11 50 26 28 0.58 1.32 9 56 47 29 (incl. 0.8 1.85 11 77 76 90 87 79 66 AM_(H)1/AM_(L)1) 30 0.69 1.55 11 40 16 31 0.56 1.96 12 12 −11 32 0.21 1.11 8 46 7 33 1.24 1.15 13 68 43 34 0.74 0.81 11 36 8 35 0.71 1.37 9 65 21 36 0.57 1.21 7 78 32 37 0.59 1.0 8 71 3 38 0.65 1.43 8 63 −38 39 0.28 1.23 7 43 −21 40 0.35 2.48 9 50 −39 41 0.64 1.61 8 49 −19 42 0.12 1.04 8 87 68 96 92 80 66 43 0.21 1.12 11 79 34 44 0.32 1.33 8 68 −3 45 0.74 1.68 10 40 −16 46 0.58 1.74 10 64 7

TABLE 6 shows IL-17RA non-clonal hybridoma supernatant screening data. The % positive and MFI columns show results from flow cytometry (FACS). The % positive columns show inhibition of biotin-huIL-17A binding to huIL-17RA⁺ CHO cells by the non-clonal hybridoma supernatants. The MFI column shows inhibition of biotinylated huIL-17A binding to cyno IL-17RA⁺ CHO cells by the non-clonal hybridoma supernatants. The first 2 HFF bioassay columns are IL-17A/HFF bioassay with non-clonal hybridoma supernatants and the last 4 bioassay columns are repeat IL-17A/HFF bioassay results with selected non-clonal hybridoma supernatants. A number of supernatants were selected for sub-cloning.

TABLE 7 HFF bioassay 1:4 1:32 1:128 % % inhibition of positive MFI IL-6 Production Neg. Cntl 1.09 1.57 10 IL-17 biot. (500 ng/ml) 8.85 10.22 77 Supernatant I.D.  1 1.85 1.33 10 29 9 21  2 1.08 1.46 16 90 61 50  3 1.29 1.39 22 33 10 4  4 1.55 1.33 18 53 66 58  5 1.69 0.7 8 76 46 30 6 (incl. AM_(H)13/AM_(L)13) 1.52 0.89 6 73 78 75  7 1.54 0.98 7 79 71 45  8 1.78 3.44 34 73 63 30  9 6.34 8.45 53 57 48 34 10 1.23 1.58 10 82 71 31 11 1.62 2.1 28 −10 −6 −10 12 1.15 1.04 16 71 63 37 13 2.43 1.67 12 58 23 −4 14 1.43 1.03 13 42 17 18 15 1.62 1.59 18 67 59 31 16 1.79 2.2 25 61 57 45 17 0.91 1.85 10 49 54 23 18 (incl. AM_(H)12/AM_(L)12) 1 1.36 6 75 82 61 19 (incl. AM_(H)17/AM_(L)17) 1.75 1.23 8 90 81 73 20 2.31 0.49 9 35 20 38 21 (incl. AM_(H)16/AM_(L)16) 1.84 0.76 6 86 90 71

TABLE 7 shows anti-IL-17RA non-clonal hybridoma supernatant screening data. The first two columns are flow cytometry data (FACS). The % positive columns show inhibition of biotin-huIL-17A binding to huIL-17RA⁺ CHO cells by the non-clonal hybridoma supernatants. The MFI column shows inhibition of biotinylated huIL-17A binding to cynomologous IL-17RA⁺ CHO cells by the non-clonal hybridoma supernatants. The final three columns show IL-17A/HFF bioassay results with non-clonal hybridoma supernatants. Supernatants 6, 18, 19 and 21 were selected for subcloning.

TABLE 8 Low IL-17A/HFF resolution bioassay BIAcore Sub-clone ID IC₅₀ (nM) K_(D)(nM)  1. Subclone of (AM_(H)14/AM_(L)14) 0.12  0.69  2. Subclone of (AM_(H)14/AM_(L)14)2 0.20 ND  3. Subelone of (AM_(H)14/AM_(L)14)3 0.075 ND  4. Subclone of (AM_(H)21/AM_(L)21) 2.3 ND  5. Subclone of (AM_(H)21/AM_(L)21) 3.1 ND  6. Subclone of (AM_(H)21/AM_(L)21) 3.3 16.7   7. Subclone of (AM_(H)20/AM_(L)20) 8.1 ND  8. Subclone of (AM_(H)20/AM_(L)20) 6.6 ND  9. Subclone of (AM_(H)20/AM_(L)20) 6.7 11.6  10. Subclone of (AM_(H)19/AM_(L)19) 0.22 3.1 11. Subclone of (AM_(H)19/AM_(L)19) 1.1 ND 12. Subclone of (AM_(H)19/AM_(L)19) 0.50 ND 13. Subclone of (AM_(H)13/AM_(L)13) >10 7.6 14. Subclone of (AM_(H)18/AM_(L)18) 0.44 ND 15. Subclone of (AM_(H)18/AM_(L)18) 0.40 ND 16. Subclone of (AM_(H)18/AM_(L)18) 0.17 14.9  17. Subclone of (AM_(H)12/AM_(L)12) 3.5 ND 18. Subclone of (AM_(H)12/AM_(L)12) 3.7 8.2 20. Subclone of (AM_(H)12/AM_(L)12) 5.5 ND 21. Subclone of (AM_(H)17/AM_(L)17) 2.5 8.2 22. Subclone of (AM_(H)17/AM_(L)17) 5.3 ND 23. Subclone of (AM_(H)17/AM_(L)17) 0.57 ND 24. Subclone of (AM_(H)16/AM_(L)16) 1.6 ND 25. Subclone of (AM_(H)16/AM_(L)16) 2.3 6.2 26. Subclone of (AM_(H)16/AM_(L)16) 1.4 ND 27. Subclone of (AM_(H)22/AM_(L)22) 0.046 1.5 28. Subclone of (AM_(H)22/AM_(L)22) 0.09 ND 29. Subclone of (AM_(H)22/AM_(L)22) 0.07 ND ND = not determined

TABLE 8 shows IL-17A/HFF bioassay IC50 values and low resolution BIAcore® K_(D) values for subcloned hybridomas. Lower IC50 and K_(D) values in the IL-17A/HFF IL-17RA binding assays showed that the IL-17RA mAbs inhibited binding of IL-17A to IL-17 receptor A. Antibodies were selected for further characterization based on low K_(D) values for inhibiting IL-17A binding to human IL-17RA.

Example 5

IL-17RA human mAb clones having the heavy and light chain sequences (AM_(H)22/AM_(L)22), (AM_(H)19/AM_(L)19), (AM_(H)18/AM_(L)18) and (AM_(H)14/AM_(L)14) were selected for further bioassay characterization. TABLE 9 below shows IC50 values for the selected Abs in the HFF bioassay and a primary lung fibroblast bioassay against both IL-17A and IL-17F.

TABLE 9 IL-17A/HFF IL-17F/HFF IL-17A/lung IL-17RA mAb IC50 (nM) IC50(nM) fibroblast IC50(nM) (AM_(H)14/AM_(L)14) 0.13 0.067 0.04 (AM_(H)22/AM_(L)22) 0.10 0.033 0.14 (AM_(H)19/AM_(L)19) 0.20 0.087 0.22 (AM_(H)18/AM_(L)18) 0.33 0.073 0.081

The selected human mAbs inhibited IL-17A binding to IL-17RA. In addition to the lower IC50 values observed for IL-17A binding to IL-17RA, the selected human mAbs exhibited reduced IC50 values inhibiting the binding of IL-17F to IL-17RA (second column). Therefore, the selected human mAbs inhibit both IL-17A-IL-17RA binding and IL-17F-IL-17RA binding.

Example 6

Exemplary IL-17RA human mAbs were tested in a cynomolgus bioassay utilizing the cynomolgus-derived kidney epithelial cell line JTC-12 stimulated with cynomolgus IL-17A. FIG. 4 shows IL-17RA mAbs having the heavy and light chain sequences (AM_(H)22/AM_(L)22), (AM_(H)19/AM_(L)19), (AM_(H)18/AM_(L)18) and (AM_(H)14/AM_(L)14) in the inhibition of cynomolgus IL-17A-induced IL-6 production from JTC-12 cells. The (----) line depicts the positive control value of cynomologous IL-17 in combination with TNF-alpha. The (-.-.-) line depicts the positive control value of cynomologous TNF-alpha. The (....) line depicts the media control value. JTC-12 cells were preincubated for 30 mins with anti-IL-17RA mAbs and then stimulated overnight with cynomolgus IL-17A (5 ng/ml) and human TNF-alpha (5 ng/ml). FIG. 7 shows that each antibody was able to inhibit cynomolgous IL-17A from binding IL-17RA and inhibit IL-17RA activation, as determined by IL-6 production from JTC-12 cells. The IL-17RA antibody (AM_(H)14/AM_(L)14) was able to antagonize cynomolgous IL-17A-induced IL-6 production from JTC-12 cells with an IC50 of approximately 1.2 nM.

Example 7

In vitro binding of IL-17RA mAbs was assayed. The binding affinities of IL-17RA antibodies were measured by surface plasmon resonance using a Biacore 3000® instrument by standard methods known in the art. Antibody candidates were captured on CM4 chips derivatized with goat anti-human IgG (H+L) antibody (Jackson Immuno Research, Bar Harbor, Me.). A CM4 chip coated with goat anti-human IgG (H+L) antibody but without captured antibody was used as a reference. Soluble huIL-17RA-FLAG-polyHis (SEQ ID NO:431) at a concentration range of 0.46-1000 nM was flowed over the chips for 2 minutes (association phase) followed by a 15-30 minute disassociation phase. FLAG peptide, Asp-Tyr-Lys-Asp-Asp-Asp-Asp-Lys (DYKDDDDK) (SEQ ID NO:447) as described in Hopp et al., Bio/Technology 6:1204, 1988, and U.S. Pat. No. 5,011,912 enables rapid assay and facile purification of expressed recombinant protein. Reagents useful for preparing fusion proteins in which the FLAG peptide is fused to a given polypeptide are commercially available (Sigma, St. Louis, Mo.).

Experiments were conducted at 25° C. using a 50 uL/min flow rate. Data was fit to a 1:1 Model+Local Rmax using BIAeval Software® (v4.1).

TABLE 10 Human Antibody k_(a) (1/Ms) K_(D) (1/s) K_(A) (1/M) K_(D) (M) (AM_(H)14/AM_(L)14) 2.60 × 10⁵ 6.22 × 10⁻⁵ 4.18 × 10⁹ 2.39 × 10⁻¹⁰ (AM_(H)22/AM_(L)22) 2.35 × 10⁵ 1.17 × 10⁻⁴ 2.01 × 10⁹ 4.98 × 10⁻¹⁰ (AM_(H)19/AM_(L)19) 1.42 × 10⁵ 1.14 × 10⁻⁴ 1.25 × 10⁹ 8.02 × 10⁻¹⁰ (AM_(H)18/AM_(L)18) 1.02 × 10⁵ 1.01 × 10⁻³ 1.01 × 10⁸ 9.88 × 10⁻⁹ 

TABLE 10 shows the K_(D) of the human mAb clones was on the order of 10⁻¹⁰ to 10⁻⁹, with the clone having the heavy and light chain sequences (AM_(H)14/AM_(L)14) having the highest affinity. Each of the human monoclonal antibodies' kinetic data was consistent with the equilibrium data. The antibody with the heavy and light chain variable sequences (AM_(H)14/AM_(L)14; SEQ ID NO:14 and SEQ ID NO:40, respectively) had the highest affinity for IL-17RA, as well as the slowest off-rate.

Example 8

Studies were conducted to determine where the various IL-17RA neutralizing antibodies bound on human IL-17RA. The ForteBio™ Octet System is one of several systems and techniques available for measuring antibody binding. The methods used for screening antibody binding essentially followed the manufacturer's recommendations. For more information see www.fortebio.com. In brief, streptavidin sensors (ForteBio™) were presoaked for 10 minutes in PBSAT (1% BSA/PBS+0.05% Tween20® (polyoxyethylene sorbitan monolaurate). Biotinylated AM_(H)14/AM_(L)14 at 10 ug/mL in PBSAT was loaded onto the sensors for 900 seconds. A new baseline was run for 600 seconds in PBSAT. Wild-type IL-17RA-FLAG-polyHis (SEC ID NO:431) at 10 ug/mL in PBSAT was then bound to the sensors for 900 seconds. A new baseline was established for 600 seconds in PBSAT. 200 nM of the following mAbs AM_(H)22/AM_(L)22, AM_(H)19/AM_(L)19, and AM_(H)18/AM_(L)18 were associated for 900 seconds, followed by dissociation for 900 seconds in PBSAT. The data showed that AM_(H)18/AM_(L)18 did not compete with AM_(H)14/AM_(L)14 for binding, showing that AM_(H)14/AM_(L)14 and AM_(H)18/AM_(L)18 bind to different neutralizing determinants. AM_(H)22/AM_(L)22 and AM_(H)19/AM_(L)19 did not bind in the presence of AM_(H)14/AM_(L)14, suggesting that all three of these antibodies bind to the same or to a similar neutralizing determinant and therefore are considered to bin together.

Example 9

Cross-competition studies were performed to determine IL-17RA binding characteristics of exemplary IL-17RA neutralizing antibodies. A modification of the multiplexed binning method described by Jia, et al. was used (see Jia, et al., J. Immun. Meth., 2004, 288:91-98). The method employed the Bio-Plex Workstation and software (BioRad, Hercules, Calif.), as well as reagents from Luminex® Corp. (Austin, Tex.). The manufacturers' basic protocols were followed except where noted below (see www.bio-rad.com and www.luminexcorp.com for details). Each bead code of streptavidin-coated Luminex® beads (Luminex®, #L100-LIXX-01, where “XX” specifies the bead code) were incubated in 150 ul of 50 ug/ml biotinylated monovalent mouse-anti-human IgG capture antibody (BD Pharmingen, Becton Dickinson, Franklin Lakes, N.J., product #555785) for 1 hour at room temperature in the dark and then washed 3 times with PBSAT. The mouse-anti-human IgG coating was evaluated and the beads quantified by FACS. Each bead code was separately incubated with 10 ul of anti-IL-17RA antibody for 1 hour at room temperature and then washed. The beads were pooled and then dispensed to a 96-well filter plate (Millipore, Billerica, Mass., product #MSBVN1250). 80 ul of 2 ug/ml IL-17RA (SEQ ID NO:431) was added to half the wells and buffer to the other half and incubated at room temperature for 1 hour then washed with PBSAT. 10 ul of an anti-IL-17RA antibody was added to one well with IL-17RA (SEQ ID NO:431) and one well without IL-17RA and incubated at room temperature for 1 hour then washed with PBSAT. An irrelevant human-IgG (Jackson Labs., Bar Harbor, Me., product #009-000-003) was included as a negative control. 50 ul PE-conjugated monovalent mouse-anti-human IgG (BD Pharmingen, Becton Dickinson, Franklin Lakes, N.J., #555787) was added to each well and incubated at room temperature for 1 hour and then washed with PBSAT. The PE-tagged monovalent antibody will detect the presence of the second mAb added to the well, but not the first mAb captured by the monovalent mouse-anti-human IgG antibody. Beads were resuspended in 120 ul PBSAT and at least 100 events/bead code were collected on the Bio-Plex workstation as per the manufacturer's recommended protocol.

Median Fluorescent Intensity (MFI) of the antibody pair without IL-17RA was subtracted from the MFI signal of the corresponding reaction containing IL-17RA to normalize for background noise. The criteria for determining if two antibodies cross-competed with each other and therefore “binned” together was a matter of determining the degree to which the second antibody was detectable. If the normalized MFI was higher than the highest of any of the following three values, then the anti-IL-17RA antibodies were considered to be simultaneously bound to IL-17RA and were considered to be in different bins (i.e., the antibodies did not cross-compete): the normalized MFI is greater than 3 times the MFI value of the antibody paired with itself, or 3 times the MFI value of the antibody paired with a huIgG control, or a MFI of 300. Generally speaking, antibodies assigned to different bins bind different parts of IL-17RA and antibodies assigned to the same bin(s) bind similar parts of IL-17RA.

FIGS. 8A and 8B show the results of multiplexed binning of anti-IL-17RA antibodies. Shaded values indicate antibody pairs that bind to IL-17RA simultaneously, suggesting that these antibodies bind to different neutralizing determinants. Boxed values indicate antibodies paired against themselves and cross-compete. The following monoclonal human antibodies containing the ascribed heavy and light variable domains were tested: A: AM_(H)11/AM_(L)11, B: AM_(H)4/AM_(L)4, C: AM_(H)8/AM_(L)8, D: AM_(H)7/AM_(L)7, E: AM_(H)6/AM_(L)6, F: AM_(H)10/AM_(L)10, G: AM_(H)18/AM_(L)18, H: AM_(H)1/AM_(L)1, I: AM_(H)22/AM_(L)22, J: AM_(H)23/AM_(L)23, K: AM_(H)14/AM_(L)14, L: AM_(H)19/AM_(L)19, M: AM_(H)12/AM_(L)12, N: AM_(H)17/AM_(L)17, O: AM_(H)16/AM_(L)16, P: AM_(H)26/AM_(L)26, Q: AM_(H)21/AM_(L)21, and R: AM_(H)20/AM_(L)20.

FIGS. 8A and 8B also show that antibodies A: AM_(H)11/AM_(L)11, B: AM_(H)4/AM_(L)4, C: AM_(H)8/AM_(L)8, D: AM_(H)7/AM_(L)7, E: AM_(H)6/AM_(L)6, F: AM_(H)10/AM_(L)10, and G: AM_(H)18/AM_(L)18 competed with one another for binding to human IL-17RA and as a consequence fell into a defined group (Bin 1). In general, antibodies I: AM_(H)22/AM_(L)22, J: AM_(H)23/AM_(L)23, K: AM_(H)14/AM_(L)14, L: AM_(H)19/AM_(L)19, M: AM_(H)12/AM_(L)12, N: AM_(H)17/AM_(L)17, O: AM_(H)16/AM_(L)16 competed with one another for binding to human IL-17RA and as a consequence fell into a defined group (Bin 3). Generally speaking, the antibodies of Bin 1 did not compete with the antibodies of Bin 3.

Antibody H: AM_(H)1/AM_(L)1 was unique in its competition pattern and formed Bin 2, but is most similar to Bin 3. Antibody P: AM_(H)26/AM_(L)26 formed Bin 4 and showed little cross-competition with any of the other antibodies, suggesting a neutralizing determinant unique to this antibody. Antibodies Q: AM_(H)21/AM_(L)21 and R: AM_(H)20/AM_(L)20, showed individually unique competition patterns, but with considerable similarities to Bin 3 antibodies, and formed Bins 5 and 6, respectively. This data provides evidence of several species within a subgenus of cross-competing antibodies.

Example 10

As described above, antibodies that bind human IL-17RA and inhibit, or neutralize, the binding of IL-17A and/or IL-17F were created and characterized. To determine the neutralizing determinants on human IL-17RA that these various IL-17RA antibodies bound, a number of chimeric human/mouse IL-17RA proteins were constructed. This method takes advantage of the non-cross reactivity of the various IL-17RA antibodies with mouse IL-17RA. For each chimera, one or two regions of human IL-17RA extracellular domain (SEQ ID NO:431) was/were replaced with the corresponding region(s) of mouse IL-17RA (SEQ ID NO:432). FIG. 9 shows mouse IL-17RA (SEQ ID NO:432) and the 5 domains, A, B, C, D, E, and F that replaced the counterpart domains in the human IL-17RA sequence. Such techniques are known in the art, see for example Stemmer, W. P. C. et al., 1995 Gene 164:49-53.

Six single-region and 8 double-region chimeras were constructed in pTT5 vectors. Chimeric constructs A through F (single region chimeras) were made synthetically by PCR annealing of 65-mer sense and antisense oligonucleotides which span the protein from a Sal1 site 5′ of the initiation codon to a Not1 site 3′ of the termination codon. The template used in the first round of PCR was a mix of oligos (sense and antisense) spanning the region from the Sal1 site to the Not1 site. PCR was done in 2 steps as follows:

Double chimeric constructs were made by digestion of single chimeras A through D with Sal1 and Sac1 restriction enzymes and a 3-way ligation with Sac1 and Not1 digested chimeras E and F using pTT5 as the expression vector. The chimeras, huIL-17RA-FLAG-polyHis (SEQ ID NO:431), and muIL-17RA-FLAG-polyHis (SEQ ID NO:432) were expressed transiently using 2936-E cells (available from the National Research Council of Canada (NRCC); see NRCC document L-11565 for further information) as host cells in roller bottles. Such transient expression techniques are well known in the art, see for example Durocher, Y. et al., 2002 Nucleic Acids Res. January 15; 30(2):E9. The supernatants were purified using a HisTrap™ HP column as per the manufacturer's general guidelines (GE Healthcare, Piscataway N.J.) and eluted using a standard imidazole gradient (see manufacturer's recommended protocols). Purified protein was desalted into PBS, pH 7.2.

The chimeras were aligned using standard analysis tools, such as ClustalW (EMBL-EBI). The resulting chimeric proteins are shown in FIGS. 10A-10D. With reference to FIGS. 9 and 10A-10D, Chimera A (SEQ ID NO:433) is human IL-17RA extracellular domain with mouse Domain A; Chimera B (SEQ ID NO:434) is human IL-17RA extracellular domain with mouse Domain B; Chimera C (SEQ ID NO:435) is human IL-17RA extracellular domain with mouse Domain C; Chimera D (SEQ ID NO:436) is human IL-17RA extracellular domain with mouse Domain D; Chimera E (SEQ ID NO:437) is human IL-17RA extracellular domain with mouse Domain E; Chimera F (SEQ ID NO:438) is human IL-17RA extracellular domain with mouse Domain F; Chimera G (SEQ ID NO:439) is human IL-17RA extracellular domain with mouse Domains A and E; Chimera H (SEQ ID NO:440) is human IL-17RA extracellular domain with mouse Domains B and E; Chimera I (SEQ ID NO:441) is human IL-17RA extracellular domain with mouse Domains C and E; Chimera J (SEQ ID NO:442) is human IL-17RA extracellular domain with mouse Domains D and E; Chimera K (SEQ ID NO:443) is human IL-17RA extracellular domain with mouse Domains A and F; Chimera L (SEQ ID NO:444) is human IL-17RA extracellular domain with mouse Domains B and F; Chimera M (SEQ ID NO:445) is human IL-17RA extracellular domain with mouse Domains C and F; and Chimera N (SEQ ID NO:446) is human IL-17RA extracellular domain with mouse Domains D and F.

Using methods similar to those described in Example 9, multiplex analysis using the Bio-Plex Workstation and software (BioRad, Hercules, Calif.) was performed to determine neutralizing determinants on human IL-17RA by analyzing exemplary human IL-17RA mAbs differential binding to chimeric versus wild-type IL-17RA proteins. Twelve bead codes of pentaHis-coated beads (Qiagen, Valencia, Calif.; see www1.qiagen.com) were used to capture histidine-tagged protein. The 12 bead codes allowed the multiplexing of 11 chimeric and the wild type human IL-17RA.

To prepare the beads, 100 ul of wild-type IL-17RA supernatant from transient expression culture and 100 ul of 2.5 ug/ml chimeric protein were bound to penta-His-coated beads overnight at 4° C. or 2 hours at room temperature with vigorous shaking. The beads were washed as per the manufacturer's protocol and the 12 bead set was pooled and aliquoted into 2 or 3 columns of a 96-well filter plate (Millipore, Billerica, Mass., product #MSBVN1250) for duplicate or triplicate assay points, respectively. 100 ul anti-IL-17RA antibodies in 4-fold dilutions were added to the wells, incubated for 1 hour at room temperature, and washed. 100 ul of a 1:100 dilution of PE-conjugated anti-human IgG Fc (Jackson Labs., Bar Harbor, Me., product #109-116-170) was added to each well, incubated for 1 hour at room temperature and washed. Beads were resuspended in 1% BSA, shaken for 3 minutes, and read on the Bio-Plex workstation. Antibody binding to IL-17RA chimeric protein was compared to antibody binding to the human IL-17RA wild-type from the same pool. A titration of antibody over approximately a 5 log scale was performed. Median Fluorescence Intensity (MFI) of chimeric proteins was graphed as a percent of maximum wild-type human IL-17RA signal. Mutations (i.e., mouse domains) that increase the EC50 (expressed in nM) for the IL-17RA mAb by 3-fold or greater (as calculated by GraphPad Prism®) were considered to have negatively affected IL-17RA mAb binding. Through these methods, neutralizing determinants for various IL-17RA antibodies were elucidated.

FIG. 11 is a table summarizing the IL-17RA mAbs capacity to bind the various chimeric proteins. Shaded values denote where the IL-17RA mAb did not meet the criteria for binding to that particular chimeric protein (“n.d.,” i.e., “not determined” means that the chimera was not assayed). As described above, EC50 values are provided. A zero value indicates that antibody binding was ablated. The underlined value was assigned an EC50 value by the GraphPad Prism® even though the titration curve was essentially flat. TABLE 11 shows the control values in nM for the assay.

TABLE 11 huWT 3 × wt 2 × wt mAb mu WT ctrl ctrl ctrl AM_(H)18/AM_(L)18 0.000 0.061 0.182 0.121 AM_(H)1/AM_(L)1 1.879 0.134 0.403 0.269 AM_(H)22/AM_(L)22 0.000 0.043 0.128 0.085 AM_(H)14/AM_(L)14 3416.000 0.027 0.082 0.055 AM_(H)19/AM_(L)19 770.100 0.062 0.187 0.125 AM_(H)23/AM_(L)23 0.000 0.053 0.158 0.106 AM_(H)26/AM_(L)26 0.000 0.281 0.843 0.562 AM_(H)21/AM_(L)21 0.196 0.018 0.055 0.037 AM_(H)20/AM_(L)20 1.333 0.022 0.066 0.044

As can be seen in FIG. 11, at least three neutralizing determinants were identified based on those regions affecting the binding of neutralizing IL-17RA antibodies, namely Domain B spanning amino acids 75-96 of human IL-17RA (SEQ ID NO:431), Domain C spanning amino acids 128-154 of human IL-17RA (SEQ ID NO:431), and Domain D spanning amino acids 176-197 of human IL-17RA (SEQ ID NO:431). Domain B spanning amino acids 75-96 of human IL-17RA (SEQ ID NO:431) negatively affected the binding of neutralizing antibodies AM_(H)1/AM_(L)1 and AM_(H)23/AM_(L)23. Domain C spanning amino acids 128-154 of human IL-17RA (SEQ ID NO:431) negatively affected the binding of neutralizing antibodies AM_(H)22/AM_(L)22 and AM_(H)23/AM_(L)23. Domain D spanning amino acids 176-197 of human IL-17RA (SEQ ID NO:431) negatively affected the binding of neutralizing antibodies AM_(H)1/AM_(L)1, AM_(H)22/AM_(L)22, AM_(H)14/AM_(L)14, AM_(H)19/AM_(L)19, AM_(H)23/AM_(L)23, AM_(H)21/AM_(L)21, and AM_(H)20/AM_(L)20. The binding characteristics of the IL-17RA antibodies in relation to where the antibodies bound on human IL-17RA was confirmed by the double chimeras. Thus, Domain B, C, and D are considered neutralizing determinants.

Example 11

As described above, antibodies that bind human IL-17RA and inhibit, or neutralize, the binding of IL-17A and/or IL-17F were created and characterized. To determine the neutralizing determinants on human IL-17RA that these various IL-17RA antibodies bound, a number of mutant IL-17RA proteins were constructed having arginine substitutions at select amino acid residues of human IL-17RA. Arginine scanning is an art-recognized method of evaluating where antibodies, or other proteins, bind to another protein, see for example Nanevicz, T., et al., 1995, J. Biol. Chem., 270:37, 21619-21625 and Zupnick, A., et al., 2006, J. Biol. Chem., 281:29, 20464-20473. In general, the arginine sidechain is positively charged and relatively bulky as compared to other amino acids, which may disrupt antibody binding to a region of the antigen where the mutation is introduced. Arginine scanning is a method that determines if a residue is part of a neutralizing determinant and/or an epitope.

95 amino acids distributed throughout the human IL-17RA extracellular domain were selected for mutation to arginine. The selection was biased towards charged or polar amino acids to maximize the possibility of the residue being on the surface and reduce the likelihood of the mutation resulting in misfolded protein. FIG. 12 depicts the amino acid residues that were replaced with an arginine residue in SEQ ID NO:431. Using standard techniques known in the art, sense and anti-sense oligonucleotides containing the mutated residues were designed based on criteria provided by Stratagene Quickchange® II protocol kit (Stratagene/Agilent, Santa Clara, Calif.). Mutagenesis of the wild-type (WT) HuIL-17RA-Flag-pHis was performed using a Quickchange® II kit (Stratagene). All chimeric constructs were constructed to encode a FLAG-histidine tag (six histidines) on the carboxy terminus of the extracellular domain to facilitate purification via the poly-His tag.

Multiplex analysis using the Bio-Plex Workstation and software (BioRad, Hercules, Calif.) was performed to determine neutralizing determinants on human IL-17RA by analyzing exemplary human IL-17RA mAbs differential binding to arginine mutants versus wild-type IL-17RA proteins. Twelve bead codes of pentaHis-coated beads (Qiagen, Valencia, Calif.; see www1.qiagen.com) were used to capture histidine-tagged protein. The 12 bead codes allowed the multiplexing of 11 IL-17RA arginine mutants and wild-type human IL-17RA (SEQ ID NO:431).

To prepare the beads, 100 ul of wild-type IL-17RA and IL-17RA arginine mutant supernatants from transient expression culture were bound to penta-His-coated beads overnight at 4° C. or 2 hours at room temperature with vigorous shaking. The beads were washed as per the manufacturer's protocol and the 12 bead set was pooled and aliquoted into 2 or 3 columns of a 96-well filter plate (Millipore, Bellerica, Mass., product #MSBVN1250) for duplicate or triplicate assay points, respectively. 100 ul anti-IL-17RA antibodies in 4-fold dilutions were added to the wells, incubated for 1 hour at room temperature, and washed. 100 ul of a 1:100 dilution of PE-conjugated anti-human IgG Fc (Jackson Labs., Bar Harbor, Me., product #109-116-170) was added to each well, incubated for 1 hour at room temperature and washed. Beads were resuspended in 1% BSA, shaken for 3 minutes, and read on the Bio-Plex workstation. Antibody binding to IL-17RA arginine mutant protein was compared to antibody binding to the human IL-17RA wild-type from the same pool. A titration of antibody over approximately a 5 log scale was performed. Median Fluorescence Intensity (MFI) of IL-17RA arginine mutant proteins was graphed as a percent of maximum wild-type human IL-17RA signal. Those mutants for which signal from all the antibodies are below 30% of wild-type IL-17RA were deemed to be either of too low a protein concentration on the bead due to poor expression in the transient culture or possibly misfolded and were excluded from analysis: these were T51R, K53R, 55R, H64R, D75R, E110R, Q118R, T121, E123R, S147R, H148R, E158R, T160R, H163R, K191R, T193R, E213R, H251R, T269R, H279R, and D293R of SEQ ID NO:431. Mutations (i.e., arginine substitutions) that increase the EC50 for the IL-17RA mAb by 3-fold or greater (as calculated by GraphPad Prism®) were considered to have negatively affected IL-17RA mAb binding. Through these methods, neutralizing determinants and epitopes for various IL-17RA antibodies were elucidated.

FIG. 13 illustrates titration curves of various IL-17RA mAbs binding to the D152R IL-17RA mutant (i.e., the aspartic acid at position 152 of SEQ ID NO:431 was mutagenized to be an arginine). Antibodies AM_(H)1/AM_(L)1, AM_(H)22/AM_(L)22, AM_(H)14/AM_(L)14, AM_(H)19/AM_(L)19, AM_(H)23/AM_(L)23, AM_(H)21/AM_(L)21, and AM_(H)20/AM_(L)20 lost the capacity to bind the D152R IL-17RA mutant. Antibodies AM_(H)18/AM_(L)18 and AM_(H)26/AM_(L)26 were only marginally affected but did not meet the cutoff criteria.

A summary of the arginine scan, binning, and chimera data is presented in FIG. 14. The arginine scan methodology identified several neutralizing determinants: AM_(H)18/AM_(L)18 bound a domain spanning amino acids 220-284 of human IL-17RA (SEQ ID NO:431); AM_(H)1/AM_(L)1 bound a domain focused on amino acid residue 152 of human IL-17RA (SEQ ID NO:431); AM_(H)22/AM_(L)22 bound a domain spanning amino acids 152-198 of human IL-17RA (SEQ ID NO:431); AM_(H)14/AM_(L)14 bound a domain spanning amino acids 152-297 of human IL-17RA (SEQ ID NO:431); AM_(H)19/AM_(L)19 bound a domain spanning amino acids 152-186 of human IL-17RA (SEQ ID NO:431); AM_(H)23/AM_(L)23 bound a domain spanning amino acids 97-297 of human IL-17RA (SEQ ID NO:431); AM_(H)26/AM_(L)26 bound a domain spanning amino acids 138-270 of human IL-17RA (SEQ ID NO:431); AM_(H)21/AM_(L)21 bound a domain spanning amino acids 113-198 of human IL-17RA (SEQ ID NO:431); and AM_(H)20/AM_(L)20 bound a domain spanning amino acids 152-270 of human IL-17RA (SEQ ID NO:431).

All of the residues shown in FIG. 14 have been shown to reduce binding of a neutralizing human monoclonal antibody that specifically binds to human IL-17RA. 

1. An isolated monoclonal antibody, or IL-17RA-binding fragment thereof, that specifically binds to IL-17RA and competes for binding with an antibody selected from the group consisting of: A. an isolated antibody, or IL-17RA-binding fragment thereof, comprising a. a light chain variable domain sequence that is at least 80% identical to a light chain variable domain sequence of AM_(L)2, 3, 5, 9, 10, 12, 14-17, and 19-25 (SEQ ID NOs:28, 29, 31, 35, 36, 38, 40-43, and 45-53, respectively); b. a heavy chain variable domain sequence that is at least 80% identical to a heavy chain variable domain sequence of AM_(H)2, 3, 5, 9, 10, 12, 14-17, and 19-25 (SEQ ID NOs:2, 3, 5, 9, 10, 12, 14-17, and 19-25, respectively); c. the light chain variable domain of (a) and the heavy chain variable domain of (b); wherein said antibody specifically binds to human IL-17RA; B. an isolated antibody, or IL-17RA-binding fragment thereof, comprising a. a light chain CDR1 (SEQ ID NO:188), CDR2 (SEQ ID NO:189), CDR3 (SEQ ID NO:190) and a heavy chain CDR1 (SEQ ID NO:110), CDR2 (SEQ ID NO:111), CDR3 (SEQ ID NO:112) of antibody AM-2; b. a light chain CDR1 (SEQ ID NO:191), CDR2 (SEQ ID NO:192), CDR3 (SEQ ID NO:193) and a heavy chain CDR1 (SEQ ID NO:113), CDR2 (SEQ ID NO:114), CDR3 (SEQ ID NO:115) of antibody AM-3; c. a light chain CDR1 (SEQ ID NO:197), CDR2 (SEQ ID NO:198), CDR3 (SEQ ID NO:199) and a heavy chain CDR1 (SEQ ID NO:119), CDR2 (SEQ ID NO:120), CDR3 (SEQ ID NO:121) of antibody AM-5; d. a light chain CDR1 (SEQ ID NO:209), CDR2 (SEQ ID NO:210), CDR3 (SEQ ID NO:211) and a heavy chain CDR1 (SEQ ID NO:131), CDR2 (SEQ ID NO:132), CDR3 (SEQ ID NO:133) of antibody AM-9; e. a light chain CDR1 (SEQ ID NO:212), CDR2 (SEQ ID NO:213), CDR3 (SEQ ID NO:214) and a heavy chain CDR1 (SEQ ID NO:134), CDR2 (SEQ ID NO:135), CDR3 (SEQ ID NO:136) of antibody AM-10; f. a light chain CDR1 (SEQ ID NO:218), CDR2 (SEQ ID NO:219), CDR3 (SEQ ID NO:220) and a heavy chain CDR1 (SEQ ID NO:140), CDR2 (SEQ ID NO:141), CDR3 (SEQ ID NO:142) of antibody AM-12; g. a light chain CDR1 (SEQ ID NO:224), CDR2 (SEQ ID NO:225), CDR3 (SEQ ID NO:226) and a heavy chain CDR1 (SEQ ID NO:146), CDR2 (SEQ ID NO:147), CDR3 (SEQ ID NO:148) of antibody AM-14; h. a light chain CDR1 (SEQ ID NO:227), CDR2 (SEQ ID NO:228), CDR3 (SEQ ID NO:229) and a heavy chain CDR1 (SEQ ID NO:149), CDR2 (SEQ ID NO:150), CDR3 (SEQ ID NO:151) of antibody AM-15; i. a light chain CDR1 (SEQ ID NO:230), CDR2 (SEQ ID NO:231), CDR3 (SEQ ID NO:232) and a heavy chain CDR1 (SEQ ID NO:152), CDR2 (SEQ ID NO:153), CDR3 (SEQ ID NO:154) of antibody AM-16; j. a light chain CDR1 (SEQ ID NO:233), CDR2 (SEQ ID NO:234), CDR3 (SEQ ID NO:235) and a heavy chain CDR1 (SEQ ID NO:155), CDR2 (SEQ ID NO:156), CDR3 (SEQ ID NO:157) of antibody AM-17; k. a light chain CDR1 (SEQ ID NO:239), CDR2 (SEQ ID NO:240), CDR3 (SEQ ID NO:241) and a heavy chain CDR1 (SEQ ID NO:161), CDR2 (SEQ ID NO:162), CDR3 (SEQ ID NO:163) of antibody AM-19; l. a light chain CDR1 (SEQ ID NO:242), CDR2 (SEQ ID NO:243), CDR3 (SEQ ID NO:244) and a heavy chain CDR1 (SEQ ID NO:164), CDR2 (SEQ ID NO:165), CDR3 (SEQ ID NO:166) of antibody AM-20; m. a light chain CDR1 (SEQ ID NO:245), CDR2 (SEQ ID NO:246), CDR3 (SEQ ID NO:247) and a heavy chain CDR1 (SEQ ID NO:167), CDR2 (SEQ ID NO:168), CDR3 (SEQ ID NO: 169) of antibody AM-21; n. a light chain CDR1 (SEQ ID NO:248), CDR2 (SEQ ID NO:249), CDR3 (SEQ ID NO:250) and a heavy chain CDR1 (SEQ ID NO:170), CDR2 (SEQ ID NO:171), CDR3 (SEQ ID NO:172) of antibody AM-22; o. a light chain CDR1 (SEQ ID NO:251), CDR2 (SEQ ID NO:252), CDR3 (SEQ ID NO:253) and a heavy chain CDR1 (SEQ ID NO:173), CDR2 (SEQ ID NO:174), CDR3 (SEQ ID NO:175) of antibody AM-23; p. a light chain CDR1 (SEQ ID NO:254), CDR2 (SEQ ID NO:255), CDR3 (SEQ ID NO:256) and a heavy chain CDR1 (SEQ ID NO:173), CDR2 (SEQ ID NO:174), CDR3 (SEQ ID NO:175) of antibody AM-23; q. a light chain CDR1 (SEQ ID NO:257), CDR2 (SEQ ID NO:258), CDR3 (SEQ ID NO:259) and a heavy chain CDR1 (SEQ ID NO:176), CDR2 (SEQ ID NO:177), CDR3 (SEQ ID NO:178) of antibody AM-24; r. a light chain CDR1 (SEQ ID NO:260), CDR2 (SEQ ID NO:261), CDR3 (SEQ ID NO:262) and a heavy chain CDR1 (SEQ ID NO:179), CDR2 (SEQ ID NO:180), CDR3 (SEQ ID NO:181) of antibody AM-25; wherein said antibody specifically binds to human IL-17RA; and C. an isolated antibody, or IL-17RA-binding fragment thereof, comprising a. a light chain variable domain and a heavy chain variable domain of AM_(L)2/AM_(H)2 (SEQ ID NO:28/SEQ ID NO:2); b. a light chain variable domain and a heavy chain variable domain of AM_(L)3/AM_(H)3 (SEQ ID NO:29/SEQ ID NO:3); c. a light chain variable domain and a heavy chain variable domain of AM_(L)5/AM_(H)5 (SEQ ID NO:31/SEQ ID NO:5); d. a light chain variable domain and a heavy chain variable domain of AM_(L)9/AM_(H)9 (SEQ ID NO:35/SEQ ID NO:9); e. a light chain variable domain and a heavy chain variable domain of AM_(L)10/AM_(H)10 (SEQ ID NO:36/SEQ ID NO:10); f. a light chain variable domain and a heavy chain variable domain of AM_(L)12/AM_(H)12 (SEQ ID NO:38/SEQ ID NO:12); g. a light chain variable domain and a heavy chain variable domain of AM_(L)14/AM_(H)14 (SEQ ID NO:40/SEQ ID NO:14); h. a light chain variable domain and a heavy chain variable domain of AM_(L)15/AM_(H)15 (SEQ ID NO:41/SEQ ID NO:15); i. a light chain variable domain and a heavy chain variable domain of AM_(L)16/AM_(H)16 (SEQ ID NO:42/SEQ ID NO:16); j. a light chain variable domain and a heavy chain variable domain of AM_(L)17/AM_(H)17 (SEQ ID NO:43/SEQ ID NO:17); k. a light chain variable domain and a heavy chain variable domain of AM_(L)19/AM_(H)19 (SEQ ID NO:45/SEQ ID NO:19); l. a light chain variable domain and a heavy chain variable domain of AM_(L)20/AM_(H)20 (SEQ ID NO:46/SEQ ID NO:20); m. a light chain variable domain and a heavy chain variable domain of AM_(L)21/AM_(H)21 (SEQ ID NO:47/SEQ ID NO:21); n. a light chain variable domain and a heavy chain variable domain of AM_(L)22/AM_(H)22 (SEQ ID NO:48/SEQ ID NO:22); o. a light chain variable domain and a heavy chain variable domain of AM_(L)23/AM_(H)23 (SEQ ID NO:49 or SEQ ID NO:50/SEQ ID NO:23); p. a light chain variable domain and a heavy chain variable domain of AM_(L)24/AM_(H)24 (SEQ ID NO:51/SEQ ID NO:24); q. a light chain variable domain and a heavy chain variable domain of AM_(L)25/AM_(H)25 (SEQ ID NO:52/SEQ ID NO:25); wherein said antibody specifically binds to human IL-17RA.
 2. The antibody of claim 1, wherein said antibody is selected from the group consisting of: A. an isolated antibody, or IL-17RA-binding fragment thereof, comprising a. a light chain variable domain sequence that is at least 80% identical to a light chain variable domain sequence of AM_(L)9, 14, 16, 17, 19-23v2, and 26 (SEQ ID NOs:35, 40, 42, 43, 45-50, and 53, respectively); b. a heavy chain variable domain sequence that is at least 80% identical to a heavy chain variable domain sequence of AM_(H)9, 14, 16, 17, 19-23, and 26 (SEQ ID NOs:9, 14, 16, 17, 19-23, and 26, respectively); c. the light chain variable domain of (a) and the heavy chain variable domain of (b); wherein said antibody specifically binds to human IL-17RA; B. an isolated antibody, or IL-17RA-binding fragment thereof, comprising a. a light chain CDR1 (SEQ ID NO:209), CDR2 (SEQ ID NO:210), CDR3 (SEQ ID NO:211) and a heavy chain CDR1 (SEQ ID NO:131), CDR2 (SEQ ID NO:132), CDR3 (SEQ ID NO:133) of antibody AM-9; b. a light chain CDR1 (SEQ ID NO:224), CDR2 (SEQ ID NO:225), CDR3 (SEQ ID NO:226) and a heavy chain CDR1 (SEQ ID NO:146), CDR2 (SEQ ID NO:147), CDR3 (SEQ ID NO:148) of antibody AM-14; c. a light chain CDR1 (SEQ ID NO:230), CDR2 (SEQ ID NO:231), CDR3 (SEQ ID NO:232) and a heavy chain CDR1 (SEQ ID NO:152), CDR2 (SEQ ID NO:153), CDR3 (SEQ ID NO:154) of antibody AM-16; d. a light chain CDR1 (SEQ ID NO:233), CDR2 (SEQ ID NO:234), CDR3 (SEQ ID NO:235) and a heavy chain CDR1 (SEQ ID NO:155), CDR2 (SEQ ID NO:156), CDR3 (SEQ ID NO:157) of antibody AM-17; e. a light chain CDR1 (SEQ ID NO:239), CDR2 (SEQ ID NO:240), CDR3 (SEQ ID NO:241) and a heavy chain CDR1 (SEQ ID NO:161), CDR2 (SEQ ID NO:162), CDR3 (SEQ ID NO:163) of antibody AM-19; f. a light chain CDR1 (SEQ ID NO:242), CDR2 (SEQ ID NO:243), CDR3 (SEQ ID NO:244) and a heavy chain CDR1 (SEQ ID NO:164), CDR2 (SEQ ID NO:165), CDR3 (SEQ ID NO:166) of antibody AM-20; g. a light chain CDR1 (SEQ ID NO:245), CDR2 (SEQ ID NO:246), CDR3 (SEQ ID NO:247) and a heavy chain CDR1 (SEQ ID NO:167), CDR2 (SEQ ID NO:168), CDR3 (SEQ ID NO:169) of antibody AM-21; h. a light chain CDR1 (SEQ ID NO:248), CDR2 (SEQ ID NO:249), CDR3 (SEQ ID NO:250) and a heavy chain CDR1 (SEQ ID NO:170), CDR2 (SEQ ID NO:171), CDR3 (SEQ ID NO:172) of antibody AM-22; i. a light chain CDR1 (SEQ ID NO:251), CDR2 (SEQ ID NO:252), CDR3 (SEQ ID NO:253) and a heavy chain CDR1 (SEQ ID NO:173), CDR2 (SEQ ID NO:174), CDR3 (SEQ ID NO:175) of antibody AM-23; j. a light chain CDR1 (SEQ ID NO:254), CDR2 (SEQ ID NO:255), CDR3 (SEQ ID NO:256) and a heavy chain CDR1 (SEQ ID NO:173), CDR2 (SEQ ID NO:174), CDR3 (SEQ ID NO:175) of antibody AM-23; k. a light chain variable domain and a heavy chain variable domain of AM_(L)26/AM_(H)26 (SEQ ID NO:53/SEQ ID NO:26); wherein said antibody specifically binds to human IL-17RA; and C. an isolated antibody, or IL-17RA-binding fragment thereof, comprising a. a light chain variable domain and a heavy chain variable domain of AM_(L)9/AM_(H)9 (SEQ ID NO:35/SEQ ID NO:9); b. a light chain variable domain and a heavy chain variable domain of AM_(L)14/AM_(H)14 (SEQ ID NO:40/SEQ ID NO:14); c. a light chain variable domain and a heavy chain variable domain of AM_(L)16/AM_(H)16 (SEQ ID NO:42/SEQ ID NO:16); d. a light chain variable domain and a heavy chain variable domain of AM_(L)17/AM_(H)17 (SEQ ID NO:43/SEQ ID NO:17); e. a light chain variable domain and a heavy chain variable domain of AM_(L)19/AM_(H)19 (SEQ ID NO:45/SEQ ID NO:19); f. a light chain variable domain and a heavy chain variable domain of AM_(L)20/AM_(H)20 (SEQ ID NO:46/SEQ ID NO:20); g. a light chain variable domain and a heavy chain variable domain of AM_(L)21/AM_(H)21 (SEQ ID NO:47/SEQ ID NO:21); h. a light chain variable domain and a heavy chain variable domain of AM_(L)22/AM_(H)22 (SEQ ID NO:48/SEQ ID NO:22); i. a light chain variable domain and a heavy chain variable domain of AM_(L)23/AM_(H)23 (SEQ ID NO:49 or SEQ ID NO:50/SEQ ID NO:23); j. a light chain variable domain and a heavy chain variable domain of AM_(L)26/AM_(H)26 (SEQ ID NO:53/SEQ ID NO:26); wherein said antibody specifically binds to human IL-17RA.
 3. The antibody of claim 1, wherein said antibody selected from the group consisting of: A. an isolated antibody, or IL-17RA-binding fragment thereof, comprising a. a light chain variable domain sequence that is at least 80% identical to a light chain variable domain sequence of AM_(L)12, 14, 16, 17, 19, and 22 (SEQ ID NOs:38, 40, 42, 43, 45, and 48 respectively); b. a heavy chain variable domain sequence that is at least 80% identical to a heavy chain variable domain sequence of AM_(H)12, 14, 16, 17, 19, and 22 (SEQ ID NOs:12, 14, 16, 17, 19, and 22, respectively); c. the light chain variable domain of (a) and the heavy chain variable domain of (b); wherein said antibody specifically binds to human IL-7RA; B. an isolated antibody, or IL-17RA-binding fragment thereof, comprising a. a light chain CDR1 (SEQ ID NO:218), CDR2 (SEQ ID NO:219), CDR3 (SEQ ID NO:220) and a heavy chain CDR1 (SEQ ID NO:140), CDR2 (SEQ ID NO:141), CDR3 (SEQ ID NO:142) of antibody AM-12; b. a light chain CDR1 (SEQ ID NO:224), CDR2 (SEQ ID NO:225), CDR3 (SEQ ID NO:226) and a heavy chain CDR1 (SEQ ID NO:146), CDR2 (SEQ ID NO:147), CDR3 (SEQ ID NO:148) of antibody AM-14; c. a light chain CDR1 (SEQ ID NO:230), CDR2 (SEQ ID NO:231), CDR3 (SEQ ID NO:232) and a heavy chain CDR1 (SEQ ID NO:152), CDR2 (SEQ ID NO:153), CDR3 (SEQ ID NO:154) of antibody AM-16; d. a light chain CDR1 (SEQ ID NO:233), CDR2 (SEQ ID NO:234), CDR3 (SEQ ID NO:235) and a heavy chain CDR1 (SEQ ID NO:155), CDR2 (SEQ ID NO:156), CDR3 (SEQ ID NO:157) of antibody AM-17; e. a light chain CDR1 (SEQ ID NO:239), CDR2 (SEQ ID NO:240), CDR3 (SEQ ID NO:241) and a heavy chain CDR1 (SEQ ID NO:161), CDR2 (SEQ ID NO:162), CDR3 (SEQ ID NO:163) of antibody AM-19; f. a light chain CDR1 (SEQ ID NO:248), CDR2 (SEQ ID NO:249), CDR3 (SEQ ID NO:250) and a heavy chain CDR1 (SEQ ID NO:170), CDR2 (SEQ ID NO:171), CDR3 (SEQ ID NO:172) of antibody AM-22; wherein said antibody specifically binds to human IL-17RA; and C. an isolated antibody, or IL-17RA-binding fragment thereof, comprising a. a light chain variable domain and a heavy chain variable domain of AM_(L)12/AM_(H)12 (SEQ ID NO:38/SEQ ID NO:12); b. a light chain variable domain and a heavy chain variable domain of AM_(L)14/AM_(H)14 (SEQ ID NO:40/SEQ ID NO:14); c. a light chain variable domain and a heavy chain variable domain of AM_(L)16/AM_(H)16 (SEQ ID NO:42/SEQ ID NO:16); d. a light chain variable domain and a heavy chain variable domain of AM_(L)17/AM_(H)17 (SEQ ID NO:43/SEQ ID NO:17); e. a light chain variable domain and a heavy chain variable domain of AM_(L)19/AM_(H)19 (SEQ ID NO:45/SEQ ID NO:19); c. a light chain variable domain and a heavy chain variable domain of AM_(L)22/AM_(H)22 (SEQ ID NO:48/SEQ ID NO:22); wherein said antibody specifically binds to human IL-17RA.
 4. The antibody of claim 1, wherein said antibody is selected from the group consisting of: A. an isolated antibody, or IL-17RA-binding fragment thereof, comprising a. a light chain variable domain sequence that is at least 80% identical to a light chain variable domain sequence SEQ ID NO: 40; b. a heavy chain variable domain sequence that is at least 80% identical to a heavy chain variable domain sequence of SEQ ID NO:14; c. the light chain variable domain of (a) and the heavy chain variable domain of (b); wherein said antibody specifically binds to human IL-17RA; B. an isolated antibody, or IL-17RA-binding fragment thereof, comprising a light chain CDR1 (SEQ ID NO:224), CDR2 (SEQ ID NO:225), CDR3 (SEQ ID NO:226) and a heavy chain CDR1 (SEQ ID NO:146), CDR2 (SEQ ID NO:147), CDR3 (SEQ ID NO:148); wherein said antibody specifically binds to human IL-17RA; and C. an isolated antibody, or IL-17RA-binding fragment thereof, comprising a light chain variable domain of SEQ ID NO:40 and a heavy chain variable domain SEQ ID NO:14; wherein said antibody specifically binds to human IL-17RA.
 5. The antibody of claim 1, wherein said antibody is selected from the group consisting of: a. a human antibody; b. a humanized antibody; c. a chimeric antibody; d. a monoclonal antibody; e. an antigen-binding antibody fragment; f. a single chain antibody; g. a diabody; h. a triabody; i. a tetrabody; j. a Fab fragment; k. a F(ab′)2 fragment; l. an IgD antibody; m. an IgE antibody; n. an IgM antibody; o. an IgG1 antibody; p. an IgG2 antibody; q. an IgG3 antibody; and r. an IgG4 antibody.
 6. The antibody of claim 5, wherein said antibody inhibits human IL-17A from binding to human IL-17RA.
 7. The antibody of claim 6, wherein said antibody inhibits human IL-17A and IL-17F from binding to human IL-17RA.
 8. The antibody of claim 6, wherein said antibody inhibits human IL-17A or IL-17F from binding to human IL-17RA.
 9. An isolated monoclonal antibody, or IL-17RA-binding fragment thereof, selected from the group consisting of: a) a monoclonal antibody that specifically binds human IL-17RA of SEQ ID NO:431 but does not specifically bind to a chimeric polypeptide consisting of SEQ ID NO:434; b) a monoclonal antibody that specifically binds human IL-17RA of SEQ ID NO:431 but does not specifically bind to a chimeric polypeptide consisting of SEQ ID NO:435; and c) a monoclonal antibody that specifically binds human IL-17RA of SEQ ID NO:431 but does not specifically bind to a chimeric polypeptide consisting of SEQ ID NO:436.
 10. An isolated monoclonal antibody, or IL-17RA-binding fragment thereof, that specifically binds a neutralizing determinant selected from the group consisting of: a) a polypeptide comprising amino acids 75-96 of SEQ ID NO:431 of human IL-17RA; b) a polypeptide comprising amino acids 128-154 of SEQ ID NO:431 of human IL-17RA; c) a polypeptide comprising amino acids 176-197 of SEQ ID NO:431 of human IL-17RA; d) a polypeptide comprising amino acids 152-297 of SEQ ID NO:431 of human IL-17RA; e) a polypeptide comprising amino acids 220-284 of SEQ ID NO:431 of human IL-17RA; f) a polypeptide comprising amino acids 152-198 of SEQ ID NO:431 of human IL-17RA; g) a polypeptide comprising amino acids 152-186 of SEQ ID NO:431 of human IL-17RA; h) a polypeptide comprising amino acids 97-297 of SEQ ID NO:431 of human IL-17RA; i) a polypeptide comprising amino acids 138-270 of SEQ ID NO:431 of human IL-17RA; j) a polypeptide comprising amino acids 113-198 of SEQ ID NO:431 of human IL-17RA; and k) a polypeptide comprising amino acids 152-270 of SEQ ID NO:431 of human IL-17RA.
 11. An isolated monoclonal antibody, or IL-17RA-binding fragment thereof, that specifically binds human IL-17RA of SEQ ID NO:431, but does not specifically bind said IL-17RA having any one of the following amino acid substitutions E97R, E113R, S115R, H138R, D152R, D154R, E156R, K166R, Q176R, S177R, D184R, E186R, S198R, H215R, S220R, T228R, T235R, E241R, H243R, L270R, Q284R, or H297R of SEQ ID NO:431.
 12. The antibody of claim 11, wherein said antibody specifically binds human IL-17RA of SEQ ID NO:431, but does not specifically bind said IL-17RA having any one of the following amino acid substitutions D152R, D154R, E156R, D184R, E186R, or H297R of SEQ ID NO:431.
 13. The antibody of claim 11, wherein said antibody specifically binds human IL-17RA of SEQ ID NO:431, but does not specifically bind said IL-17RA having the aspartic acid residue at position 152 of SEQ ID NO:431 substituted with an arginine.
 14. The antibody of claim 11, wherein said antibody specifically binds an epitope defined by any one of amino acids D152, D154, E156, D184, E186, or H297 of SEQ ID NO:431.
 15. The antibody of claim 14, wherein said antibody specifically binds an epitope defined by at least two of the following amino acids D152, D154, E156, D184, E186, or H297 of SEQ ID NO:431.
 16. The antibody of claim 14, wherein said antibody specifically binds an epitope defined by at least three of the following amino acids D152, D154, E156, D184, E186, or H297 of SEQ ID NO:431.
 17. The antibody of claim 14, wherein said antibody specifically binds an epitope defined by at least four of the following amino acids D152, D154, E156, D184, E186, or H297 of SEQ ID NO:431.
 18. The antibody of claim 14, wherein said antibody specifically binds an epitope defined by at least five of the following amino acids D152, D1154, E156, D184, E186, or H297 of SEQ ID NO:431.
 19. The antibody of claim 14, wherein said antibody specifically binds an epitope defined by amino acids D152, D154, E156, D184, E186, H297 of SEQ ID NO:431.
 20. An isolated monoclonal antibody, or IL-17RA-binding fragment thereof, that specifically binds to IL-17RA and competes for binding with an antibody comprising: a. a heavy chain CDR1 comprising an amino acid sequence selected from the group consisting of: i. X₁YGIS, wherein X₁ is selected from the group consisting of R, S and G; b. a heavy chain CDR2 comprising an amino acid sequence selected from the group consisting of: i. WISX₁YX₂GNTX₃YAQX₄X₅QG, wherein X₁ is selected from the group consisting of A, X₂ is selected from the group consisting of N, S and K, X₃ is selected from the group consisting of N and K, X₄ is selected from the group consisting of K and N, and X₅ is selected from the group consisting of L and F; c. a heavy chain CDR3 comprising an amino acid sequence selected from the group consisting of: i. X₁QLX₂X₃DY, wherein X₁ is selected from the group consisting of R and K, X₂ is selected from the group consisting of Y, V, and A, and X₃ is selected from the group consisting of F and L; ii. X₁QLX₂FDY, wherein X₁ is selected from the group consisting of R and K, and X₂ is selected from the group consisting of Y and V; d. a light chain CDR1 comprising an amino acid sequence selected from the group consisting of: i. RASQSX₁X₂X₃X₄LA, wherein X₁ is selected from the group consisting of V and I, X₂ is selected from the group consisting of I and S, X₃ is selected from the group consisting of S and T, X₄ is selected from the group consisting of N and S, and X₅ is selected from the group consisting of A and N; ii. RASQSX₁SSNLA, wherein X₁ is selected from the group consisting of V and I; e. a light chain CDR2 comprising an amino acid sequence selected from the group consisting of: i. X₁X₂STRAX₃, wherein X₁ is selected from the group consisting of G and D, X₂ is selected from the group consisting of A and T, and X₃ is selected from the group consisting of T and A; ii. X₁ASTRAX₂, wherein X₁ is selected from the group consisting of G and D, and X₂ is selected from the group consisting of A and T; and f. a light chain CDR3 comprising an amino acid sequence selected from the group consisting of: i. QQYDX₁WPLT, wherein X₁ is selected from the group consisting of N, T, and I.
 21. The antibody of claim 20, wherein said antibody comprises: a. a heavy chain CDR1 amino acid sequence comprising X₁YGIS, wherein X₁ is selected from the group consisting of R, S and G; b. a heavy chain CDR2 amino acid sequence comprising WISX₁YX₂GNTX₃YAQX₄X₅QG, wherein X₁ is selected from the group consisting of A, X₂ is selected from the group consisting of N, S and K, X₃ is selected from the group consisting of N and K, X₄ is selected from the group consisting of K and N, and X₅ is selected from the group consisting of L and F; c. a heavy chain CDR3 amino acid sequence comprising X₁QLX₂FDY, wherein X₁ is selected from the group consisting of R and K, and X₂ is selected from the group consisting of Y and V; d. a light chain CDR1 amino acid sequence comprising RASQSX₁SSNLA, wherein X₁ is selected from the group consisting of V and I; e. a light chain CDR2 amino acid sequence comprising X₁ASTRAX₂, wherein X₁ is selected from the group consisting of G and D, and X₂ is selected from the group consisting of A and T; and f. a light chain CDR3 amino acid sequence comprising QQYDX₁WPLT, wherein X₁ is selected from the group consisting of N, T, and I.
 22. The antibody of claim 20, wherein said antibody is selected from the group consisting of: a. a human antibody; b. a humanized antibody; c. a chimeric antibody; d. a monoclonal antibody; e. an antigen-binding antibody fragment; f. a single chain antibody; g. a diabody; h. a triabody; i. a tetrabody; j. a Fab fragment; k. a F(ab′)2 fragment; l. an IgD antibody; m. an IgE antibody; n. an IgM antibody; o. an IgG1 antibody; p. an IgG2 antibody; q. an IgG3 antibody; and r. an IgG4 antibody.
 23. The antibody of claim 22, wherein said antibody inhibits human IL-17A from binding to human IL-17RA.
 24. The antibody of claim 22, wherein said antibody inhibits human IL-17A and IL-17F from binding to human IL-17RA.
 25. The antibody of claim 22, wherein said antibody inhibits human IL-17A or IL-17F from binding to human IL-17RA. 